FIRE FLY's hop-up packing for the Maruzen APS-II is highly popular for its quality and effectiveness.
It also has excellent stability.
Characteristics: The BB bullet is caught in the depression in the center, and a consistent hop rotation is applied at a consistent position. For sweet BBs, the white ones are relatively soft, while the black ones are hard.
*Hop-up pads are a part of the HOP (hop-up) system of air guns, made of rubber that gives BBs rotation . The rotation creates different airflows above and below, generating lift (the Magnus effect), which increases the flight distance of the BBs.