The American Defense Delta Mount is without a doubt one of the most reliable mounts on the market. With the SOCOM approved design it has been adapted to the FN SCAR and is quickly becoming one of the more popular mounts. The Delta Mount is precision machined from 6061 T6 Aluminum with hard coat anodizing for extra durability. The patented Auto Lock lever system securely attaches you optic in its original place each time if leaves your firearm. Note: Auto Lock Lever system is adjustable to fit both spec and out of spec rail systems