The Hollis Mod-1 Scuba Breathing Pod, known as the MOD-1, features the patented Kirby Morgan two-chamber design (Mask and POD) to support multiple configurations for Open Circuit and Closed Circuit Rebreather systems. This modular approach is used by United States Marines Combat Divers and other military dive teams around the world, reflecting its suitability for demanding scuba operations and challenging diving environments.

Designed for compatibility with standard scuba gear, the MOD-1 enables flexible breathing configurations for open-circuit diving or closed-circuit rebreather missions, combining reliability with practical ease of use in the field.