Advantage Arms! :righton:
I have one for my G20/21. Excellent for plinking and easy on the wallet.
Very reliable, but reloading the 10rd mags gets a little tiring after a while.
I picked up the kit and 2 extra mags brand new from a Glock armorer at a gun show in Tampa, FL for $260-.
I don't know much about the competition "Ceiner?", but I've heard the AA is the way to go.
Only negative is that I wish California's laws on mags were better as the AA mags could easily fit 20+ if not for the company's home state restrictions.
I believe the Ceiner kit has higher mag capability, but I may be wrong.
Hope this helps.
Stay safe!