ADAPT Modular Technology; Engineered Silence - Baffles are machined from 17-4 Stainless Steel barstock, with two indexing tabs for proper alignment; Non-slotted Piston - This drastically lowers gas blowback for a more enjoyable shooting experience; Revolutionary Mounting System; Parts Compatibility - The Obsidian45 is fully compatible with Obsidian9 accessories; Belt Fed Rated - Machined from top of the line materials to not only last a lifetime, but withstand any rate of fire; Removable Front Caps; 9mm Front Caps available; Pistons work as a Front Cap Tool; Unconditional Lifetime Warranty