Safety Block for V2 Gearbox
The safety block is a small plastic piece found in a V2 gearbox, primarily on M4/M16 and acts as a trigger block. When you go to pull the trigger on safe mode, the fire selector has pushed the safety block into position, preventing the trigger from being pulled.
Since virtually all M4 triggers are made of metal, and even some steel, it is of no surprise that over time the safetly block wears away. If you find you have a bit of slack on the trigger in safe, it is recommended to replace the safety block as it reduces the likelihood of an accidental discharge.
Included in the package is the block, spring and securing screw.