Product Name: O RingMaterial: nitrile rubberColor: BlackQuantity: 50 pcsOuter diameter: 12 mmInner diameter: 7 mmThickness: 2.5 mmWeight: eight gPackage Contents: 50 x NBR O RingOnly the above package content, other merchandise will not be included.Note: Light shooting and diversified displays may cause the colour of the object within the photo slightly various from the genuine thing. The measurement allowed error is +/-1-3cm.