Hop-up, (High Operation Power Up), is basically describes the back spin trajectory of an BB pellets, by adjusting the Hop-Up to increase their range and accuracy. As the pellet shoots through this hop up bucking, the friction creates the spin, it tends to roll and backspin. The Maple Leaf hop up has been adjusted to the specified degree so it solely depends on what the player needs. The "concave" shape bucking, it will provide you the best hop up effect ever and is made specifically for all GBB Pistol out there.