The STTI ST23 does not have a blow-back - only allows you to tighten the hammer - that's why the replica is addressed primarily to users who prefer combat values over the precision of mapping and functionality of all mechanisms.
It is made of plastic (ABS). The magazine, outer barrel, hammer, both fuses, magazine release lever, cock, mechanic (inside the gun) and other details are made of metal. In addition, the replica is equipped with a sound suppressor modeled on the original, which in addition to its normal function increases the replica's power to 380 fps. Due to the very high power, great caution is recommended when using this replica. The gun without the silencer reaches 300fps, with the silencer mounted the power increases to 380fps.