The SXT Series Handguards feature a free-floating AR-15 handguard with an M-LOK attachment system. The simple clamping system uses two cross bolts which fit into the barrel nut for a rapid and easy installation. (The old SXS Series clamping system used a bias block on the bottom to secure the forearm to the barrel nut which required knurling). Inside diameter 1.25", Outside diameter 1.60".
Determined at checkout.