RA-Tech posted another video of their upgrade parts for the WE Airsoft TA-2015 Gas Blowback (or known as the WE P-90 GBB). Mainly these are steel parts such as bolt stopper and the parts inside the trigger box such as the hammer, sear, etc. Check out the video below to find out the if the performance or experience using the TA-2015 GBB is enhanced: