USGI Chemical-Biological Mask Internal Drink Tube (M40, M42, M45)

US Genuine Issue Internal Drink Tube for M40, M42, and M45 series chemical-biological masks - in new unissued condition in original sealed packaging. 

The internal drink tube is a core component of the modern hydration systems used within the JSLIST ensemble and alongside the JSGPM (Joint Service General Purpose Mask).  Its primary purpose is to allow the wearer to drink from a canteen or hydration bladder while maintaining a chemical-biological seal.

Qty: 5x per-package.

NSN

• 4240-01-441-0557

Features

• Chemical Resistance: Manufactured from medical-grade, chemical-agent-resistant rubber (typically silicone-based) to ensure it does not degrade when exposed to toxic environments.
• Hands-Free Operation: The tube is designed to be grasped by the mouth from inside the mask, allowing the user to drink without using their hands to position it.
• Customizable Length: The tube is purposely long and is intended to be trimmed by the user during initial fitting to sit comfortably at their mouth.
• Fail-Safe Seal: It works in conjunction with an external coupler and internal valves to prevent the backflow of liquid or the accidental intake of contaminated air.
• MOPP Integration: Allows for essential hydration while in full JSLIST (MOPP 4) gear, which is critical for preventing heat-related injuries during extended operations.
• Versatility: While officially for the M40/M45 series, its standard sizing makes it a popular "universal" replacement or upgrade for other CBRN masks not originally equipped with a drinking system.
• Pressure Equalization: When used with an M1 Canteen Cap, the system allows the bottle to contract as liquid is drawn out and re-expand once the pressure equalizes, ensuring a steady flow of water.
• Cleaning: The tube should be regularly inspected for cracks, cuts, or clogs. It can be cleaned with warm, soapy water, and a long-reach brush is often used for the interior.
• Contamination Check: Before each use, users are trained to check all mating surfaces for contamination to avoid ingesting chemical agents.