Maintaining a flawless facial seal on your oxygen mask is non-negotiable when operating in high-altitude MFF (HALO/HAHO) windows or specialized CBRN environments. Standard mask harnesses often conflict with helmet liners, causing hotspots and dangerous air leaks. The Ops-Core O2 Mask Double Strap Kit resolves this by routing your mask retention directly onto the helmet's rail system. We offer this legitimate factory kit in two configurations: FAST & Sentry Rails or ACH Rails. This system distributes tension evenly across the face, eliminating helmet rotation and ensuring your life-support equipment stays locked down under heavy slipstreams or high-G movements. Key Features Platform-Specificc Sizing: FAST & Sentry Variant: Tailored perfectly for standard Ops-Core ARC rail channels. ACH Variant: Engineered to clear the geometry and mounting hardware of legacy ACH/MICH helmet rail conversions. Dual-Strap Stabilisation: The double strap architecture creates dual vectors of rearward tension. This keeps the mask stabilized symmetrically against the face, preventing buffeting from high-velocity aircraft exits. Rapid Snap-Fit Disconnect: Heavy-duty snap buckles allow operators to don or doff their O2 mask instantly upon landing, even while wearing wet-weather or combat gloves. Mil-Spec Environmental Resistance: Built from specialized low-temperature tolerant polymers and low-stretch webbing designed to perform flawlessly in high-altitude, sub-zero environments. Applications Military Free Fall (MFF) Operations: Vital hardware for airborne operators requiring a secure oxygen mask interface during HAHO/HALO inflight and descent phases. Specialised Tactical Units: For tactical teams integrating specialized gas or low-profile filtration masks with their existing ballistic headborne systems. Milsim & Aviation Collecting: Complete an authentic, accurate impression of modern Tier 1 operators configured for airborne deployment. Technical Highlights Helmet Compatibility: Ops-Core FAST, Sentry, or ACH/MICH configurations (Select version at checkout). Mask Compatibility: Fits standard military oxygen mask snap profiles (e.g., Gentex PHAEDRA, MBU-20/P). Kit Includes: Left and right O2 strap assemblies, quick-release buckles, and rail mounting shoes.