This is the XS Scuba XTR Extra Air Complete Backup Rescue System Features: Mini Tech Gauge (HL501) 0 to 5000 psi, wide 210 degree sweep Chromed brass case Compact First Stage (HL406) Highland DIN direct inlet Simple flow-by piston design XS Scuba PRO Valve (VX200-30N-VI) Combination DIN/Yoke outlet DIN insert included DIN Cap (HL401) Seal water out of your first stage Machined Delrin material Cylinder Choices: Aluminum 6 cu ft - neon yellow Aluminum 13 cu ft - neon yellow (pictured) Aluminum 19 cu ft - neon yellow Pony Mount (HL409) Highland design Stainless steel construction Quick & easy attachment Secure under your current BC strap Miflex (MLP40-YL) Low pressure regulator hose Length: 40 Color: yellow AltAir (RG300) Compact, low profile octopus Easy, high flow purge Built-in attachment clip for BC 90Adeg Adapter (AC910) Swivels for use by diver or buddy Chromed brass construction The XS Scuba XTR Extra Air System is a completely redundant back up air system for increased dive safety. A must for solo divers or others who must be self-reliant underwater. "