Geissele Automatics, MK4 Federal, Rail, OD Green, MLOK, AR15, 10
- M1913 picatinny rails in the 3 6 9 & 12 o'clock positions
- M-LOK slots in the 3 6 and 9 o'clock positions & in the upper 45 quadrants
- Lightweight design
- Maximum ventilation on the barrel
