diff --git a/src/buffers.rs b/src/buffers.rs
index 807f4bf..cab4f9a 100644
--- a/src/buffers.rs
+++ b/src/buffers.rs
@@ -186,7 +186,7 @@ impl<S: Surface + Default> Surfaces for SurfacePool<S> {
     }
 }
 
-pub trait Pixbuf: AsMilliwatts + IndexMut<usize, Output=Self::Pixel> {
+pub trait Pixbuf: AsMilliwatts + IndexMut<usize, Output=Self::Pixel> + Send {
     type Pixel: HardwarePixel;
     fn new() -> Self;
     fn blank(&mut self);