Comments about Product: We bought some for ourselves and other people for Christmas. My husband is a police/fireman. He has used the seatbelt cutter,but not the window hammer, hence only the four star rating. He said it worked fine. My son messed around with the hammer and said it broke glass, but it hasn't been used in an emergency situation. In the unlikely event of an underwater entrapment I've heard that it could save a life. I keep mine on my keyring.