Hop-up, (High Operation Power Up) is described as the back spin of the airsoft BBs. As the BB shoots through the hop up bucking, the friction creates the back spin, which significantly increases their range and accuracy.
The "concave" shape bucking will provide you with one the best accuracy hop up effect ever and is made specifically for AEGs. I personally consider this hop the closest you can get to the superior Extended R hop (translucent segment, leftmost on last picture), but without the need to modify the barrel and retaining fexability to adjust the lift according to your bb weight.

The colour will vary depends on the degree.

For the best range, please choose:

50 degree - for sub 300fps AEGs, and cold weather

60 degree - for 300-330fps 

70 degree - for 330-350fps 

75 degree - for 340-350fps

80 degree - over 350fps

Included is a 3D printed nub, which is original design (not Maple leaf) that boosts the effect of the concave shape of the rubber. This nub is designed a bit higher than the ordinary cylindrical nub, so you will need less hop up than before. It is made of elastomer (rubber-like plastic) to minimize the risk of piercing the bucking.

Usually, replacing the bucking and the nub is not hard, but make sure the nub does not press the bucking too much as it will jam the bbs or too close to the edge of the barrel window as this may shear the wall of the bucking!

If you are buying nubs only and you purchase 2, you will get +1 free.


Please, look at my positive feedback and buy with confidence.