I have (or had..) a Gen I Sub 2K with the S&W type 59 mag configuration, as I have a number of gen II and gen III S&Ws pistols that use these mags. I wanted to switch to the Gen II, due to all the improvements that Kel-Tec baked into it, but I didn't want to lose compatibility with the S&W 59 mag, as the Gen II Sub 2K switched to supporting the S&W M&P mag format. Can't blame Kel-Tek, most folks aren't buying the older style S&Ws these days. Anyway, I contacted Kel-Tek, to see if they would consider building a 59 compatible Gen II, perhaps using the parts from my Gen I. They offered to upgrade my Gen I to Gen II spec, which would retain the type 59 mag style, and give me all the bennies of the Gen II. For $75. No brainer. Well, got it back and it was not my Gen I, it was a new Gen II which had the proper serial number transposition to maintain the 4473 registration, and took the old Type 59 mag. Did I mention they did this for $75? Including shipping? Incredible. In all my years of dealing with techie things and customer service departments and policies, how Kel-Tec handled my request was the most impressive I have ever experienced. Much appreciation to the folks at Kel-Tek. This is how great customer service is done.