The Raven rotary machine is designed to operate over a variable voltage range depending on personal preference and the type of work being created.it can be connected to a power supply using an RCA or clip cord. The Raven is fitted with a ‘one touch hit adjuster. Settings are altered by rotating the metal adjuster knob at the top of the unit. the full range of settings can be achieved with less than one rotation. when the metal tab is covering number one, the machine is set to its hardest hit. when number 10 is covered, the machine is set to its lightest hit. Bits 1-10 change from hard to soft The needle retainer can be tightened and loosened using the adjuster knob. screw the knob gently in a clockwise direction until the pulley is in contact with the needle and keeps it in place on the rubber nipple.do not over tighten as this will put unwanted strain on the motor. If the adjustment knob is loosened during operation, the O-ring needs to be replaced, After replacing the new O-ring, a small amount of lube can be applied to make reassembly easier.