Full Sequential trigger- Also known as single shot trigger, restrictive trigger, or trigger fire mode.

This is the safest type of nail gun trigger. This trigger will only fire a nail when the controls are activated in a certain order. First, the safety contact tip must be pushed into the work piece, then the user squeezes the trigger to discharge a nail. Both the safety contact tip and the trigger must be released and activated again to fire a second nail. Nails cannot be bump fired.

• Single nail: Push safety contact, then squeeze trigger
• Multiple nails: Release both safety contact and trigger and repeat process

Contact trigger
Fires a nail when the safety contact and trigger are activated in any order. You can push the safety contact tip fist and then squeeze the trigger, or you can squeeze the trigger fist and then push the safety contact tip. If the trigger is kept squeezed, a nail will be driven each time the safety contact is pushed in. All nails can be bump fired. Also known as bump trigger, multi-shot trigger, successive trigger, dual-action, touch trip, contact trip, and bottom fire.

• Single nail: Push safety contact, then squeeze trigger, or squeeze trigger, then push safety contact
• Multiple nails: Squeeze and hold trigger, then push safety contact to fire one nail, move and push safety contact again to fire additional nails

Single Sequential trigger
Like the full sequential trigger, this trigger will only fie a nail when the controls are activated in a certain order. First, the safety contact tip must be pushed into the work piece. Then, the user squeezes the trigger to discharge a nail. To fire a second nail, only the trigger must be released. The safety contact tip can stay pressed into the work piece. Nails cannot be bump fired.

• Single nail: Push safety contact, then squeeze trigger
• Multiple nails: Release trigger, move tool, and squeeze trigger to fire additional nail

Single Actuation trigger
Like the contact trigger, this trigger will fie a single nail when the safety contact and trigger are activated in any order. A second nail can be fired by releasing the trigger, moving the tool and squeezing the trigger again without releasing the safety contact tip. Note that some manufacturers refer to these triggers as “single sequential triggers”, but they are different. The fist nail can be bump fired with a single actuation trigger but not with a true single sequential trigger.

• Single nail: Push safety contact, squeeze trigger, or squeeze trigger, then push safety contact to fie
• Multiple nails: Release trigger, move tool, and squeeze trigger to fie additional nail

The International Staple, Nail and Tool Association (ISANTA) voluntary standard includes technical definitions for trigger “actuation systems”. Tool manufacturers have names for trigger modes such as “intermittent operation method” or “precision placement driving”. Contractors and workers use their own names for triggers and operating modes such as “single shot” and “multi-shot”.