The fuses shown from left to right are: minor caliber percussion fuse, minor caliber magazine percussion fuse, major caliber percussion fuse, major caliber magazine percussion fuse, triple, double and single train time fuses. The time fuses all contain a percussion element to insure their exploding on impact if not previously exploded. No special tool is required for setting these fuses. They are made, up to 27 seconds burning time for guns of 2,600-foot seconds muzzle velocity, and up to 36 seconds for mortars and guns of 1,400-foot seconds muzzle velocity.