USED Forward Controls Design Flash Hider 5/8x24 QPQ Black. 6310RF-A1 has 6 evenly spaced ports which provides slightly better flash suppression and evenly distributes the jets inside the blast chamber of a suppressor. 6310RF-A1 has .900 x 24 external threads and a taper which are compatible with Plan B Type mounts. Do not use a crush washer if this is going to be a suppressor host. Specifications for Forward Controls Design 6310RF-A1 Flash Hider: Manufacturer: Forward Controls Design Color: Black Finish: QPQ Fabric/Material: 17-4PH Stainless Steel Threads per Inch: 5/8x24 Length: 1.725 in Weight: 1.64 oz Package Contents: Forward Controls Design 6310RF-A1 Flash Hider Single use packet of Rocksett Forward Controls Design 6310RF-A1: 6310RF-A1 Flash Hider 5/8x24 QPQ Black