This is the 9mm GAB-10 (Glock based AB10) Pistol by Freemendontask. The GAB-10 takes standard Glock mags i.e., G26,19,17 or 18. It is heavily inspired by the Intratec Tec 9 and AB-10.

You can source parts kits from a couple places:

Gunbroker.com has them occasionally; you can win auctions for under $200. Search using keywords: "Tec 9", "Tec-9", "Tec9", "AB 10", "AB-10", "AB10" (their search function sucks, so you will probably need to use each keyword).

Everygunpart.com has Tec-9/AB-10 parts listed most of the time. The kit is $300 but no auctions. Search "Tec 9" on their site and you will find them. The the AB 10s (AB10 and Tec 9 are the same gun, AB10 [After Ban 10] is just a 94 AWB compliant version)