The REO family of single circuit blasting machines are of solid state capacitor discharge design. They offer a wide variety of energy and voltage choices in a series of lightweight, portable, water and corrosion resistant enclosures. The reliable design of the units prohibits them from firing until the unit is charged to the designated voltage. Included is a safety interlock, the charge and fire switches must be both depressed to fire a blast. The unit is rendered inactive when one or both of the switches are released.