He was holding some sort of trigger in his hand!

The thing you saw is really just a kind of trigger for the machine.

Still, several research groups are trying to address the issue of environmental triggers.

Historically, the first type of trigger was the single action.

It is likely that there are a number of triggers for the behavior.

People often have more than one type of trigger for their headaches.

One shot is fired with each pull of the trigger.

It would be that easy, one squeeze of the trigger, and the job was done.

He set off some kind of trigger that brought them here.

They fire one round at a time with each pull and release of the trigger.