Product name: Nitrile rubber O Ring Material: nitrile rubber Weight: 9 g Inner diameter: eleven mm External diameter: 15 mm Thickness: 2 mm Color: Black Package content: 50 x nitrile rubber O ring Only the above package content, other merchandise are usually not included. Note: Light shooting and different reveals can cause the colour of the article within the photo a bit various from the real thing. The dimension allowed error is +/-1-3cm.