Honeywell Optima Plus calibration kit, 3/16" ID Tubing, gas cover, C-10 inlet regulator for Optima without RGC Remote Gassing Cell (contains 998-100-004 tubing, 2108D0258 gas cover, 998-100-002 C-10 regulator (2LPM), W/GAS CELL), 998-100-003 carrying case. Calibration gas cylinder not included-