The Patented Arisaka Inline Scout Mount (ISM) is designed for use with Surefire Scout Lights, the Modlite PLH and OKW weapon lights, the Arisaka 300" 600 and 18650 Series, and the Streamlight Protac Rail Mount lights. It replaces the stock Picatinny rail adapter with a low profile mount that tucks the light underneath either side of the B.E. Meyers MAWL laser/illuminator series. Three positions on the mount allow for different diameter light heads to clear the MAWL without interference. Compatible with the Modlite PLH, PLHv2 and OKW, Surefire M300A" M300B" M300C" M300V" M312" M322" M312V" M313V" M322V" M600B" M600C" M600P" M600U" M600V" M600DF" M612" M622" M603V" M612V" M622V" Streamlight Protac Rail Mount 1" 2 and HL-X (non-laser), CD REIN, and Arisaka 300" 600 and 18650 Series.Features : ,Length: 1.265";"Thickness: 0.2"" Weight: 0.6 oz ,Hardware: One 10-32x1.25" Torx cap head screw, two 8-32x3/8" Torx flat head screws, Made in the USA