If you pay attention to safety, you must get it. People say - it will get used just once or twice in lifetime so why buy?, to that I say - if it can save your life once a while then it's worth buying. Note: this is the thing that should not be kept in your trunk but rather stick it somewhere near driver seat so you can get it at the time of emergency. Emergencies like, car submerged under water, or in case of fire. At those moments car doors and seat belts get stuck so you can slice through your belt, smash your glass and get out. I am thinking of using a double sided 3M tape and stick it either on body side pillar or under the dashboard somewhere.