Unfortunately in this lock, the alarm is activated only when the ball is inside somewhere pressed firmly (eg by a brake disc). In my MTB or that can only thank God to be mounted on the suspension so.
Better, but not as stable as the Abus Detecto RS1. One can simply activate with your finger. Unfortunately, there is no to massive chain lock. Well, now I have both on two wheels in use. In order that the protection should be quite good as you would damage the bikes massive if you want the lockpicking - I hope.