The Maple Leaf MR hop up bucking is a high quality upgrade hop up bucking made to boost the performance of your airsoft gun.  
For GBB/VSR10 spec inner barrel and without modify
Larger & wider contact area inside of BB pellet, has better hop effect with heavy BB
For Heavy BB pellet only
The "Shield" shape groove design has better hop effect when tensioner/lever press it
Retain the steel "C-ring" design for airseal from "Transformer HOP"series
The R-hop Rubber kit begin from a small group user who want to increase the range and hop effect of heavy bb. The title "R" mean the "RANGE". But it need modify the original AEG hop rubber and stick the rubber patch by yourself, so it not easy for everyone and need some airsoftgunsmith technique for that.
Compatibility :
Tokyo Marui GBB Series 
WE GBB Series
VSR-10 Series Bolt Action Rifles