uxcell 10Pcs Flexible Silicone O Ring Seal Sealing Gasket 13mm x 20mm x 3.5mm Product Name : O Ring;Material : Silicone Inside Diameter : 13mm/ 0.51";Outside Diameter : 20mm/ 0.79" Thickness : 3.5mm/ 0.14";Color : Brick Red Weight : 7g Package Content : 10 Pcs x O Ring