K4 b2 TX Module, K4 b2 RX Module, GPS Module, three (3) Rechargeable Batteries, Charge unit, two (2) flowmeters, Polar HR belt, three (3) faces masks (Adult S, M, L), Adult headcap, Adult Harness, Gas Calibration unit, PC software, Aluminium Carrying case, RS-232 cable, antenna, extra cabling for connections.