Check wirecutter or even amazon. Tempered glass is actually ridiculously easy to break even with just a spark plug in your hand, so anything with a hammer shape and the right tip is gonna do it. Just make sure there is also a seatbelt cutter on the tool.

That said, it is probably worth spending some more money to get the spring loaded type. It doesn’t take THAT much effort to smash a tempered glass window, but it is a lot easier to just push a device against it instead.