Beauty ORA Electric Roller Replacement Needle Heads Set (3 Piece)

To place the needle head on the electric roller, place the head on the end of the derma pen and then push the needle head while turning the head clockwise until the two openings on the head locked into the two round slots on the roller. You can adjust the needle length by turning the needle length adjustment part. To remove the cartridge, turn the needle head counter clockwise and pull the needle head off once the cartridge openings are no longer locked into the two round slots on the roller.