The magazine is made of metal and holds 31 BBs.
The Marui Hi-Capa 4.3 magazines and Hi-Capa 5.1 magazines only differ in the capacity (28 / 31 BBs) and in the design of the bottom plate... but both magazines fit into both GBBs.
If the magazine leaks one day, then you can find a manual here to fix that.
Also you find information about how to prevent a leaky magazine in this manual.
- Buy 3 for €40.76 each and save 5%
- Buy 5 for €39.90 each and save 7%
- Buy 7 for €39.04 each and save 9%
- Buy 9 for €38.18 each and save 11%