Horiba U-50 Series Packing List: Control Unit, Sensor Probe Unit with Cable, Calibration Cup, 500ml pH 4 solution, 250ml Model 330 reference solution, Backpack, DO membrane repair kit w/1 spare membrane cap, pH sensor, ORP Sensor, DO sensor, reference sensor, spanner wrench, cleaning brush, (4) LR14 batteries, hand strap, silicon grease