Booster Housings / Nielson devices are used on guns utilizing a browning style action or firearms that move. examples are Glocks, 1911 style firearms, CZ, FN and other pistols.
The booster housings holds a thread adapter that acts like a piston that is spring loaded which allows the firearm to cycle properly.
Without a booster housing / Nielson device the pistol with not cycle correctly and act as a single shot pistol.
Available for 9mm or .45. Uses Creative Arms LLC. thread adapters.