I have 2 ghk mags that are pretty old and kinda beat up. They both hold gas and still do work most of the time. They could use a good cleaning and lubing. I bought them used and the last guy sanded down the sides so they would fit in his magwell. I have no use for them since I rarely use the gun and I have a mag that works better for it. I will sell them for $10 each if you are interested.