Ultra-low profile SLOT-LOCK allows for easy mounting of ADI or CDI angle indicators on the Picatinny rail system under low-mounted scope tubes—without removing the scope. The SLOT-LOCK boasts three position height adjustments and left and right mounting options, and the unique lugs ensure fixed position under extreme recoil. Machined from 6061-T6 aircraft aluminum and hard anodized with military spec finishes, this is as tough as they make them.