Guarder TM Desert Eagle Recoil & Hammer Spring Set 550-700 The CMR rail also has

The CMR rail also has built in anti-rotation QD mounts in 4 positions at both ends of the rail on both sides

Compatible Tanks:  HPA and SLP tanks

adds functionality and performance improvements suitable for those looking for the best performance from their AEG

There are multiple sling mounting options featured on the stock including QD swivel sockets on both sides with a pass-through channel for loop type sling attachments and a sling slot on the front side of the butt part of the stock

How about the effort to pull back the bolt on your 500 FPS gun

Guarder TM Desert Eagle Recoil & Hammer Spring Set 550-700 The CMR rail also hasGuarder Enhanced Recoil Hammer Spring (150%) for Marui & Compatible D. Eagle Style series gas blowback Material: S303 Stainless