6.8L carbon fiber tank 4500 psi for pcp paintball HPA air guns, DOT approved, with dual gauge DIN type valve The tank is DOT certified, so you can fill it at a scuba shop, it will be faster and more convenient than charging by yourself, no need to have a big compressor at home. After full filled, you can take it out for hunting and shooting in the wild, it can help you last longer time in the wild and doing more shooting and hunting at a time. 1.Assembly includes: 1x 6.8L/416 Cu.in DOT Carbon Fiber tank 1x dual gauge DIN type tank on/off valve 1x Carrier Backpack For tank only, it weighs 8.6LB.(3.9kg). The whole system weighs 13LB.(5.9kg) For the dual gauge DIN type tank on/off valve, it has two gauges on it, the 25mm gauge will always show the pressure inside the tank, so you can check what is left in the tank anytime. The 40mm gauge shows the inline pressure when use it to fill your airguns. 6.8L/416 Cu.in is the water capacity, it is the actual volume of the tank. As for the 74 cu ft, it is in fact air capacity. 74 cu ft aoir which is not compressed, can be stored in 6.8L/416 Cu.in tank under 310bar/4500psi pressure.