Good evening to you!! The Kel-tec Sub 2000 in .40 cal will use either the Glock 23 or Glock 22 magazines. You can find them at the below link. Hope this helps. Have a good rest of your day.
🇺🇸🇺🇸 'Merica' 🇺🇸🇺🇸
budsgunshop.com/product_info.php/products_id/69488/glock+mag+g22+22rd+40s+pkg

Visit here: budsgunshop.com/product_info.php/products_id/69488/glock+mag+g22+22rd+40s+pkg

Max Sir,
Glock magazines that fit the Kel-Tec Sub 2000 in .40 caliber are typically Glock magazines designed for Glock models that share the same caliber and magazine dimensions. Specifically, the following Glock magazines are compatible:
-**Glock 22 magazines** (.40 S&W) These are the most commonly used magazines for the Kel-Tec Sub 2000 in .40 cal, as they match the caliber and fit the magazine well.
**Glock 23 magazines** (.40 S&W) Also compatible, as they share similar dimensions with the Glock 22 magazine.
Hope the above info helps Sir MAX, please take care and stay safe 🙏🏻

Here ya go below!!
budsgunshop.com/product_info.php/products_id/69488/glock+mag+g22+22rd+40s+pkg

Hi Max and welcome. Different capacity G22 40S&W Magazines available here: budsgunshop.com/search.php/q/g22+magazines -------------- Cheers, stay safe and enjoy! Drum Magazine here: budsgunshop.com/product_info.php/products_id/122813/promag+drma19+for+glock+compatible+40+s%26w+g2223+50rd+black+drum

Hi Max, The KelTec SUB-2000 in .40 caliber can use Glock 22 (GLK22) and Glock 23 (GLK23) magazines.
budsgunshop.com/product_info.php/products_id/69488/glock+mag+g22+22rd+40s+pkg ,
Stay safe & have a great day!