I'd guess they are Triple-K magazines (they say "Colt .45 Auto" on the baseplate)...I have a couple with several hundred rounds out of them with no problems. I have been told you should "tune" the feed lips of them, but I never have on mine.
Jbohio, the last time I bought from them they were going to charge me the same "handling" charge ($6.75) for two mags that they charged for a case of .223. The handling charge was in addition to shipping. They may have changed their policy since I last bought from them 2 yrs ago.