Rummbolt puts the 4UAD Smart Airsoft Hop-Up Bucking into a MK18 for a shooting test... "If you are into Airsoft for a while, you may be familiar with ‪4UAD Smart Airsoft‬: A quite popular Youtube Channel from Taiwan, dealing with innovative airsoft products. One of their latest highlights is the "Friction Pro" Hop Up bucking, an inhouse development which caused some kind of a little hype in the community. It claims to increase consistency and precision of your replica significantly. Of course, I had to test this bucking by myself - not only by installing it to one of my guns, but by actually building a complete new system around it from high quality upgrade parts. Lets get a closer look!"