What is an R-Hop? R-Hop is the revolutionary hop up modification intended to greatly increase the range of your airsoft gun. The area where the bucking would protrude though the slot cut in the barrel is replaced with what is known as a "patch." Patches come in different types and thicknesses much like hop-up buckings do. The patch is cut and shaped to fill the slot and then the small nub on the inside of the bucking (not to be confused with the primary hop up nub) is cut and sanded away. The patch will line seamlessly with the outside of the barrel and the inside bore of the barrel. Essentially, the patch replaces that nub inside the bucking to give more contact with the BB as it is ejected out the barrel. With the patch and modified bucking in tandem, a variety of primary hop up nubs can be used to achieve different hop-up trajectories depending on the guns velocity and types of BB's being used. The 3 patches are slightly different in concavity to allow you to pick the closest possible fit to your barrel diameter with the least amount of modification. These patches are excel in colder environments. For warm weather shooting, try the standard RZ R-Hop Patches! *Disclaimer: "R-Hopping" is a difficult and very precise procedure. Not all airsoft guns are guaranteed to be able to be R-Hopped. R-Hopping depends on many variables such as barrel type, bucking type, gun velocity, and BB's used. Results of different guns may vary. R-Hops also have a tendency to LOWER the guns FPS slightly for the trade off of range. This is due to additional force applied from the R-Hop to the BB. Due to the difficulty of installing a R-Hop, it is highly suggested that the R-Hop is installed professionally. Airsoft Station's experienced professional technicians can install the R Hop into your rifle at a price that can't be beat!