This magazine is made of metal and fully compatible with aftermarket airsoft guns taking M4 magazine. The capacity of this magazine is 300rds and the internal components of the magazine are imported from Japan. Extremely smooth loading of the BB means no re-wind is necessary after one full wind up.  

Selling points:

1. High Quality internal components imported from Japan
2. No Re-wind is needed ***  (One full wind up will allow you shooting all BB bullet out!!)
3. Fully Compatible with Aftermarket Airsoft Guns taking M4 Style Magazine