This is the Bottle Strap from Arctic Technical Gear which is compatible with their General Purpose Canteen pouch or GPC, Hybrid Nalgene Pouch, TCR Placard V2, MODSAW pouch and Stacked MODGP pouch.
Coming soon, it retains multiple types of Nalgene bottles and issued canteens.
All components are Berry compliant including webbing and ITW buckles.
Despite the company’s name, neither of those carriers are suitable for winter Arctic use – you’ll end up with a block of ice on your belt.