diff --git a/candle-core/src/op.rs b/candle-core/src/op.rs
index 2b57f7f7..cf99f86e 100644
--- a/candle-core/src/op.rs
+++ b/candle-core/src/op.rs
@@ -118,13 +118,22 @@ pub enum Op {
     ToDevice(Tensor),
     Transpose(Tensor, usize, usize),
     Elu(Tensor, f64),
-    CustomOp1(Tensor, std::sync::Arc<Box<dyn CustomOp1>>),
-    CustomOp2(Tensor, Tensor, std::sync::Arc<Box<dyn CustomOp2>>),
-    CustomOp3(Tensor, Tensor, Tensor, std::sync::Arc<Box<dyn CustomOp3>>),
+    CustomOp1(Tensor, std::sync::Arc<Box<dyn CustomOp1 + Send + Sync>>),
+    CustomOp2(
+        Tensor,
+        Tensor,
+        std::sync::Arc<Box<dyn CustomOp2 + Send + Sync>>,
+    ),
+    CustomOp3(
+        Tensor,
+        Tensor,
+        Tensor,
+        std::sync::Arc<Box<dyn CustomOp3 + Send + Sync>>,
+    ),
 }
 
 /// Unary ops that can be defined in user-land.
-pub trait CustomOp1: Send + Sync {
+pub trait CustomOp1 {
     // Box<dyn> does not support const yet, so use a function to get the name.
     fn name(&self) -> &'static str;
 
@@ -148,7 +157,7 @@ pub trait CustomOp1: Send + Sync {
     }
 }
 
-pub trait CustomOp2: Send + Sync {
+pub trait CustomOp2 {
     fn name(&self) -> &'static str;
 
     /// The forward pass, as run on a cpu device. Note that the storage can use arbitrary strides,
@@ -186,7 +195,7 @@ pub trait CustomOp2: Send + Sync {
     }
 }
 
-pub trait CustomOp3: Send + Sync {
+pub trait CustomOp3 {
     fn name(&self) -> &'static str;
 
     /// The forward pass, as run on a cpu device. Note that the storage can use arbitrary strides,
diff --git a/candle-core/src/quantized/mod.rs b/candle-core/src/quantized/mod.rs
index a0ed5b4d..a334b2c1 100644
--- a/candle-core/src/quantized/mod.rs
+++ b/candle-core/src/quantized/mod.rs
@@ -147,11 +147,11 @@ impl QTensor {
     }
 }
 
-pub struct QMatMul(std::sync::Arc<Box<dyn crate::CustomOp1>>);
+pub struct QMatMul(QTensor);
 
 impl QMatMul {
     pub fn from_qtensor(qtensor: QTensor) -> Self {
-        Self(std::sync::Arc::new(Box::new(qtensor)))
+        Self(qtensor)
     }
 }
 
@@ -196,6 +196,6 @@ impl crate::CustomOp1 for QTensor {
 
 impl QMatMul {
     pub fn forward(&self, xs: &Tensor) -> Result<Tensor> {
-        xs.custom_op1_arc(self.0.clone())
+        xs.apply_op1_no_bwd(&self.0)
     }
 }
diff --git a/candle-core/src/storage.rs b/candle-core/src/storage.rs
index 791b65dd..4a6cdc34 100644
--- a/candle-core/src/storage.rs
+++ b/candle-core/src/storage.rs
@@ -138,7 +138,7 @@ impl Storage {
         }
     }
 
-    pub(crate) fn custom_op1(&self, l: &Layout, c: &dyn CustomOp1) -> Result<(Self, Shape)> {
+    pub(crate) fn apply_op1(&self, l: &Layout, c: &dyn CustomOp1) -> Result<(Self, Shape)> {
         match self {
             Self::Cpu(storage) => {
                 let (storage, shape) = c.cpu_fwd(storage, l)?;
@@ -151,7 +151,7 @@ impl Storage {
         }
     }
 
-    pub(crate) fn custom_op2(
+    pub(crate) fn apply_op2(
         &self,
         l1: &Layout,
         t2: &Self,
@@ -172,7 +172,7 @@ impl Storage {
         }
     }
 
-    pub(crate) fn custom_op3(
+    pub(crate) fn apply_op3(
         &self,
         l1: &Layout,
         t2: &Self,
diff --git a/candle-core/src/tensor.rs b/candle-core/src/tensor.rs
index c14a4e39..c71ea5ec 100644
--- a/candle-core/src/tensor.rs
+++ b/candle-core/src/tensor.rs
@@ -1870,22 +1870,53 @@ impl Tensor {
         std::ptr::eq(lhs, rhs)
     }
 
+    /// Applies a unary custom op without backward support
+    pub fn apply_op1_no_bwd<C: CustomOp1>(&self, c: &C) -> Result<Self> {
+        let (storage, shape) = self.storage().apply_op1(self.layout(), c)?;
+        Ok(from_storage(storage, shape, BackpropOp::none(), false))
+    }
+
+    /// Applies a binary custom op without backward support
+    pub fn apply_op2_no_bwd<C: CustomOp2>(&self, rhs: &Self, c: &C) -> Result<Self> {
+        let (storage, shape) =
+            self.storage()
+                .apply_op2(self.layout(), &rhs.storage(), rhs.layout(), c)?;
+        Ok(from_storage(storage, shape, BackpropOp::none(), false))
+    }
+
+    /// Applies a ternary custom op without backward support
+    pub fn apply_op3_no_bwd<C: CustomOp3>(&self, t2: &Self, t3: &Self, c: &C) -> Result<Self> {
+        let (storage, shape) = self.storage().apply_op3(
+            self.layout(),
+            &t2.storage(),
+            t2.layout(),
+            &t3.storage(),
+            t3.layout(),
+            c,
+        )?;
+        Ok(from_storage(storage, shape, BackpropOp::none(), false))
+    }
+
     /// Applies a unary custom op.
-    pub fn custom_op1_arc(&self, c: Arc<Box<dyn CustomOp1>>) -> Result<Self> {
+    pub fn apply_op1_arc(&self, c: Arc<Box<dyn CustomOp1 + Send + Sync>>) -> Result<Self> {
         let (storage, shape) = self
             .storage()
-            .custom_op1(self.layout(), c.as_ref().as_ref())?;
+            .apply_op1(self.layout(), c.as_ref().as_ref())?;
         let op = BackpropOp::new1(self, |s| Op::CustomOp1(s, c.clone()));
         Ok(from_storage(storage, shape, op, false))
     }
 
-    pub fn custom_op1<C: 'static + CustomOp1>(&self, c: C) -> Result<Self> {
-        self.custom_op1_arc(Arc::new(Box::new(c)))
+    pub fn apply_op1<C: 'static + CustomOp1 + Send + Sync>(&self, c: C) -> Result<Self> {
+        self.apply_op1_arc(Arc::new(Box::new(c)))
     }
 
     /// Applies a binary custom op.
-    pub fn custom_op2_arc(&self, rhs: &Self, c: Arc<Box<dyn CustomOp2>>) -> Result<Self> {
-        let (storage, shape) = self.storage().custom_op2(
+    pub fn apply_op2_arc(
+        &self,
+        rhs: &Self,
+        c: Arc<Box<dyn CustomOp2 + Send + Sync>>,
+    ) -> Result<Self> {
+        let (storage, shape) = self.storage().apply_op2(
             self.layout(),
             &rhs.storage(),
             rhs.layout(),
@@ -1895,13 +1926,18 @@ impl Tensor {
         Ok(from_storage(storage, shape, op, false))
     }
 
-    pub fn custom_op2<C: 'static + CustomOp2>(&self, r: &Self, c: C) -> Result<Self> {
-        self.custom_op2_arc(r, Arc::new(Box::new(c)))
+    pub fn apply_op2<C: 'static + CustomOp2 + Send + Sync>(&self, r: &Self, c: C) -> Result<Self> {
+        self.apply_op2_arc(r, Arc::new(Box::new(c)))
     }
 
     /// Applies a ternary custom op.
-    pub fn custom_op3_arc(&self, t2: &Self, t3: &Self, c: Arc<Box<dyn CustomOp3>>) -> Result<Self> {
-        let (storage, shape) = self.storage().custom_op3(
+    pub fn apply_op3_arc(
+        &self,
+        t2: &Self,
+        t3: &Self,
+        c: Arc<Box<dyn CustomOp3 + Send + Sync>>,
+    ) -> Result<Self> {
+        let (storage, shape) = self.storage().apply_op3(
             self.layout(),
             &t2.storage(),
             t2.layout(),
@@ -1915,8 +1951,13 @@ impl Tensor {
         Ok(from_storage(storage, shape, op, false))
     }
 
-    pub fn custom_op3<C: 'static + CustomOp3>(&self, t2: &Self, t3: &Self, c: C) -> Result<Self> {
-        self.custom_op3_arc(t2, t3, Arc::new(Box::new(c)))
+    pub fn apply_op3<C: 'static + CustomOp3 + Send + Sync>(
+        &self,
+        t2: &Self,
+        t3: &Self,
+        c: C,
+    ) -> Result<Self> {
+        self.apply_op3_arc(t2, t3, Arc::new(Box::new(c)))
     }
 }
 
diff --git a/candle-core/tests/custom_op_tests.rs b/candle-core/tests/custom_op_tests.rs
index 55b5e894..7ec04c6a 100644
--- a/candle-core/tests/custom_op_tests.rs
+++ b/candle-core/tests/custom_op_tests.rs
@@ -39,7 +39,7 @@ fn custom_op1_no_backward() -> Result<()> {
     let cpu = &Device::Cpu;
     let t = Tensor::arange(0u32, 12u32, cpu)?.to_dtype(DType::F32)?;
     let t = (t - 5.)?;
-    let elu_t = t.custom_op1(Elu { alpha: 1. })?;
+    let elu_t = t.apply_op1_no_bwd(&Elu { alpha: 1. })?;
     assert_eq!(
         to_vec1_round(&elu_t, 4)?,
         &[-0.9933, -0.9817, -0.9502, -0.8647, -0.6321, 0.0, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0]
@@ -96,7 +96,7 @@ impl CustomOp1 for EluWithBackward {
 
     fn bwd(&self, arg: &Tensor, _res: &Tensor, grad_res: &Tensor) -> Result<Option<Tensor>> {
         let alpha = self.0.alpha;
-        let bwd = arg.custom_op1(EluBackward { alpha })?;
+        let bwd = arg.apply_op1(EluBackward { alpha })?;
         Ok(Some(grad_res.mul(&bwd)?))
     }
 }
@@ -105,7 +105,7 @@ impl CustomOp1 for EluWithBackward {
 fn custom_op1_with_backward() -> Result<()> {
     let cpu = &Device::Cpu;
     let t = candle_core::Var::new(&[-2f32, 0f32, 2f32], cpu)?;
-    let elu_t = t.custom_op1(EluWithBackward::new(2.))?;
+    let elu_t = t.apply_op1(EluWithBackward::new(2.))?;
     assert_eq!(to_vec1_round(&elu_t, 4)?, &[-1.7293, 0.0, 2.0]);
 
     let grads = elu_t.backward()?;
diff --git a/candle-examples/examples/custom-ops/main.rs b/candle-examples/examples/custom-ops/main.rs
index 63bcd83a..7f7a3f26 100644
--- a/candle-examples/examples/custom-ops/main.rs
+++ b/candle-examples/examples/custom-ops/main.rs
@@ -89,7 +89,7 @@ fn main() -> anyhow::Result<()> {
     let device = candle_examples::device(args.cpu)?;
     let t = Tensor::arange(0f32, 14f32, &device)?.reshape((2, 7))?;
     println!("{t}");
-    let t = t.custom_op1(LayerNorm { eps: 1e-5 })?;
+    let t = t.apply_op1(LayerNorm { eps: 1e-5 })?;
     println!("{t}");
     Ok(())
 }
diff --git a/candle-examples/examples/llama_multiprocess/model.rs b/candle-examples/examples/llama_multiprocess/model.rs
index ab4e382c..ad5e4cd2 100644
--- a/candle-examples/examples/llama_multiprocess/model.rs
+++ b/candle-examples/examples/llama_multiprocess/model.rs
@@ -68,7 +68,7 @@ impl CustomOp1 for AllReduce {
 }
 
 fn all_reduce_sum(x: &Tensor, comm: &Rc<Comm>) -> Result<Tensor> {
-    x.custom_op1(AllReduce { comm: comm.clone() })
+    x.apply_op1(AllReduce { comm: comm.clone() })
 }
 
 impl TensorParallelRowLinear {
diff --git a/candle-flash-attn/src/lib.rs b/candle-flash-attn/src/lib.rs
index 092743f1..3c5fd455 100644
--- a/candle-flash-attn/src/lib.rs
+++ b/candle-flash-attn/src/lib.rs
@@ -178,7 +178,7 @@ pub fn flash_attn(
         softmax_scale,
         causal,
     };
-    q.custom_op3(k, v, op)
+    q.apply_op3(k, v, op)
 }
 
 struct FlashAttnVarLen {
@@ -402,5 +402,5 @@ pub fn flash_attn_varlen(
         seqlens_q: seqlens_q.clone(),
         seqlens_k: seqlens_k.clone(),
     };
-    q.custom_op3(k, v, op)
+    q.apply_op3(k, v, op)
 }