They're top bits of kit- I got mine for £20 quid of a lad I worked with.

Originally they used to quote 18mins to get them off.

I have it on good authority that time can be halved if you know what you're doing.

BUT

The reason they're such a deterent apart from the 9 - 18 mins removal time is how noisey they are to remove.

Other ways to improve them- weld a strip across the front but inside as well as this strengthens the front from attack.

Also weld over the hole where the lock is to make it more difficult to drill the lock.

ALWAYS lock it on the tightest point.

Jake