What part is this please?

[ikarma70]

Hi guys, took my Cyma cm048 apart for the hpa conversion and the below part in the link dropped out, what is it and is it important to the conversion please?

 

http://i25.photobucket.com/albums/c56/andybike/5FCD52BF-7D6C-4C98-8637-7A367BF9E64B.jpg

[Samurai]

Safety. This moves in to stop the trigger from moving.

[ikarma70]

Thankyou, you're a lifesaver!!!!