F Superlative Arms Adjustable Bleed-Off Gas Block Clamp On AR-15, LR-308 - 378070 $89.99 SABO-DI-750CM show more like this 5.00 MidwayUSA F Superlative Arms Adjustable Bleed Off AR-15/AR-10 Gas Block, .750in, Clamp On , Melonite, Black, SABO-DI-750CM $89.99 SABODI750CM show more like this Free Shipping on most orders over $49 Optics Planet F Superlative Arms Ar-15 Clamp On Adjustable Gas Block - Ar-15 Clamp On Adjustable Gas Block .750" Black $90.99 SABO-DI-750CM show more like this $12.50 Brownells