PVS 14 upper body. fits well with both ITT double battery housing and carson/noctis milspec battery pack.

You will need proprietary M39 tube locking ring for this upper. I made the threads thicker to make it possible to FDM it.

you need 4x M2 heat inserts and 1x ¼ 20 5mm heat insert.

auto cutoff feature is optional, i havent made it but im pretty sure you can make one with either thumbtack or a piece of metal.