- When closed, the lid is held with a spring-loaded lock.
- This knife was like a switchblade, except that the blade was spring-loaded to shoot straight out of the handle and lock when you pressed the release button, rather than opening sideways.
- In the market I found almost everyone sold heavy, serrated, spring-loaded metal rattraps.
- The doors are spring-loaded so that, at the point of being halfway closed, the spring will take over and slam the door shut and hold it closed.
- If you enter the correct code, a spring-loaded door pops open, but a built-in computer will block access if five wrong codes are entered.