Spring-loaded window breaker: how does it work?

Unlike an emergency hammer, a spring-loaded window breaker needs no swing and very little force. You press it against the window and the mechanism does the work. Here is how it works, part by part.

The principle in one sentence

Inside the tube, a spring compresses when you press the tool against the window. At the end of its travel it releases all at once and drives a small, very hard tip into the glass. The energy is concentrated on a tiny point, which is enough to shatter a tempered glass side window.

The parts, one by one

• The aluminium body: smooth and light, it protects the mechanism.
• The spring: it stores energy when you press, then releases it all at once.
• The tip: small and very hard, it concentrates all the force on a single point of the glass.
• The seatbelt cutter blade: recessed in a slot, you slide the strap in without touching the blade.
• The wrist strap: to keep the tool in hand or grab it faster.
• The mount: it keeps the tool fixed in the console, always in the same place.

How to use it

1. Choose a side window, never the windscreen, which is made of laminated glass.
2. Place the tip in a lower corner of the window, where the glass is most fragile.
3. Press firmly until it clicks: the spring releases and the window shatters.
4. Clear the remaining pieces before getting out.

For the right moves in detail, read our guide how to break a car window in an emergency.

Spring or hammer: which one to choose?

A hammer needs a swing, which is hard with your seatbelt on or in a tight space. The spring-loaded model works with a simple press, with one hand, and it is more compact. That is why it fits easily in a console or a storage pocket. Find all our criteria in which window breaker to choose.

SafeCore Pro, our spring-loaded window breaker

SafeCore Pro combines a spring-loaded window breaker and a seatbelt cutter with a protected blade, in an aluminium tube supplied with its console mount.