Brand new and in stock - The Chub Nub V4 (Concave).
 
The concave design in response to a huge demand from airsofters looking to see how the Chub Nub would fair with a concave design - Works best with Silverback Buckings
 
The SRS Chub Nub V4 has been redesigned to slightly reduce the height of the nub allowing more hop flexibility. This means you can use 0.36's up to 0.48's (or even heavier) bbs. 
 
The manufacturing process has also been refined giving you a smoother finish with greater definition resulting in an exact fit for the Silverback FastHop