HPA M4 FCU box

thingiverse

https://youtu.be/DscGYS57k10 has enough room for a gorilla fcu and 250mah 2s lipo for the homies that struggle with ESG grips. public domain license, remix, reproduce, sell, whatever. no restrictions. use a m6 screw with at least 12mm of threads for the cap and a (whatever thread your gun needs) with at least 35mm of threads for the gearbox, most are m5, krytacs are m6. stock post must be under 25mm in length and the side ribs must be 4mm, some KWAs are stupid and have 5mm ribs