Loading WE M4 GBB magazines by hand is one of those things that sounds fine until you're doing it for the fifth time in a row. This adapter from Comrade Quiche makes it quick and painless, it connects your speedloader to the WE M4 mag so you can fill it up without the usual thumb fatigue.
Comrade Quiche is a well-known member of the Heavy Recoil Club community who designed this out of genuine frustration with the stock loading experience. It's a small part that makes a real difference when you're trying to stay in the game.
