Excellent purchase for its price.
It works reliably, the batteries last a long time, and it is not affected by heat or rain.
It is true that it does not "lock" when raised and simply sounds an alarm. However, it is very strong and clearly deterrent, and you can also avoid your own mistakes, i.e. lifting the bar while you have parked on top of it.

It does what it says. The only negative thing for me, and hence the rating, is that it doesn't 'lock' whether it's up or down. That means anyone can easily lift it or lower it with a little push... of course, the alarm goes off when you tamper with it.