These magazines are surprisingly strong and good! I wish they had a push nub to ensure all BB's are pushed out of the mag so you don't spill BB's, which for the price you would expect there to be a push nub... but they are made of actual steel, actual metal. You can take a magnet and stick it on these things.
The adjustable nature is great... honestly, these mags are very good. A little overpriced, but that's to be expected with the FAMAS.