The BT20B Atlas Accuracy International Spigot Bottom Rail is the same rail found in the BT20, but consists of the bottom 1913 rail ONLY. It attaches to the BT19 AAIS on the bottom and accepts any rail mounted bipod.
Machined to Picatinny rail standards from 6061-T6 aluminum with Mil-Spec Type III Class 2 finish. Available in black only.