Generals Store › 20mm Black Flip Off Cap Includes Gray Butyl Stopper. Image 1 of 2 Image 2 of 2 20mm Black Flip Off Cap Includes Gray Butyl Stopper. from $9.99 20mm Black flip off cap 20mm Blk Flip Off Cap: Select 20mm Blk Flip Off Cap 50 Pack Caps Only $9.99 100 Pack Caps Only $12.99 200 Pack Caps Only $19.99 500 Pack Caps Only $35.99 1000 Pack Caps Only $61.99 Quantity: Add To Cart Added! 20mm Black flip off cap