Each deployment of the Mammut Airbag 3.0 system uses up a refill kit. You also need to find a compressed air source to reload the cartridge. Enter the Trigger Test Tool. This handy device lets you practice deployments without emptying a cartridge. Screw the tool into the deployment mechanism, put on the backpack, and pull the handle. A clear snapping sound means you've successfully triggered the airbag. Pat yourself on the back, put the cartridge back in, and hope you don't have to use it for reals.