This is a Sticky Holsters Mag Pouch/Light Holder known as the Dual Mag Sleeve, model DMMS.
The Dual Mini Mag Sleeve is a IWB or Pocket magazine or accessory holder. This is designed for small single stack magazines. The Dual has two mag sleeves sewn together. Fits magazines similar in size or small than a Glock 43.
Features:
Ambidextrous
American Made
Latex and allergen free
Multi-Use and Multi-Fit
Part of a modular system
