No, it won't "stop" a thief but it's another layer of protection along with all the others you should be using already.
Lock them on the actual bikes if not the shed door.... You get the idea. Guessing they are vibration/motion triggered.
Be inventive. Lol
https://www.aldi.co.uk/home-protector-alarm-padlock/p/082228194505600
Father-in-law has one of those on his garage (different brand but same design).
It's bloody loud when you can't get they key to turn because it's slightly corroded and the lock is at face height!
Just what I was looking for, cheers op!
had one eventually the rain got to it [ few years??] and it went off all the time so I binned it - some years ago so perhaps this version is more robust ?
Personally I'd have them in the shed attached to the bikes themselves but wherever they are used they can't do any harm as an extra deterrent.
They are good. It bleeps first if disturbed, then second time goes off. Used one at work alongside heavy duty d-locks as we were having theft issues, knock the bike and it goes off.