Subtronics India Pvt. Ltd. Offers Pocket Type Portable Gas Monitor. Subtronics India Pvt. Ltd. Is an ISO 9001:2000 certified company. Pocket Type Portable Gas Monitor is available in two models-with probe or without probe. The operating voltage that is required for the machine is 6 volts D.C. Rechargeable batteries [NiCd]. This product features built-in beep type Alarm Siren. The operating hours of the machine is 10 Hours [1 Shift]. It weighs 120 grams only. The charger is offered with the product and is free of cost.