This particular EdGI Custom Works tuning kit was made specifically for the Tokyo Marui VSR-10 G-Spec and comes with these parts:
363mm 6.01 Precision Barrel,
Cylinder, Cylinder Head,
7mm Spring Guide,
High Pressure Piston,
Trigger Sear,
Piston Sear,
Spring Guide Stopper.
Once applied, you'll be happy to know that your bolt action sniper rifle will be one of the most precise shooting sniper rifles out there.