Disconnected car alarm
This is a somewhat unusual contraption - a car alarm sitting independent of any vehicle, with an attachment for a large battery to power the alarm. The speaker is muted so as to avoid it emitting the usual unbearable shrill siren associated with such items. You could probably practise with it until you got the hang of disarming alarms a little.
It is coloured yellow and is made of some unidentifiable material. It looks like it is completely uncharged, and is powered with a large battery. It looks like you could use it to practise disarming an alarm.