Product name: Nitrile rubber O RingMaterial: nitrile rubberWeight: nine gInner diameter: 11 mmExternal diameter: 15 mmThickness: 2 mmColor: BlackPackage content: 50 x nitrile rubber O ringOnly the above equipment content, different merchandise will not be included.Note: Light capturing and varied exhibits could cause the color of the thing in the photo somewhat various from the real thing. The dimension allowed error is +/-1-3cm.