Standard safety features include a Supplemental Restraint System (SRS) or airbag system for the driver and front seat passenger for head-on or front impact. These are impact sensors, a driver's air bag module installed at the center of the steering wheel, passenger's air bag in the glove box chamber and a sensing/ diagnostic module put at the center of the car floor pan. Here some cars also contain side-impact airbags, these are the small bags situated on the side of seat backs that fold if there is a severe side-impact collision. The Air bag inflator module This is found in the steering wheel and has a housing that contains the Air Bag and the inflator unit, as soon as the inflator receives an electrical impulse, the bag is almost inflated immediately. The passenger airbag, which is significantly larger than the driver's, is located above and behind the glove box and the trimming has grooved face which opens up upon deployment. The sensing and diagnostic module supplies current to the air bag system during an impact, checks it at engine start and informs about malfunctioning of the system through the "AIR BAG" light. To prevent any accidental activation of the SRS components while working in that area, operation of the system has to be disabled by steering the wheels to a straight ahead position, turning the ignition key to LOCK position, removing the battery's negative terminal and waiting for not less than 2 minutes. In other concerns, the airbag opening should not be placed towards the body while holding it and it's ill advise to measure the resistance of any SRS component; electrical welding equipment should not be used where there is an airbag, especially without disconnecting the airbag connectors; and one should never dispose a live airbag module irresponsibly. Concerning the removal of airbag modules it is recommended not to do it without the help of skilled personnel.