Premium Single D-Size Battery Holder with Curved Sides Physics_Alternative Energy Twenty-centimeter steel helical spring paired

Twenty-centimeter steel helical spring paired with 2kg

Used to supply rechargeable DC power for circuit experiments

expanding and closing to suit different optical-component sizes on a single bench-mounted holder

well suited to demonstrating the force on a current-carrying conductor in a magnetic field

Used to teach how AC/DC ammeters and voltmeters work

Premium Single D-Size Battery Holder with Curved Sides Physics_Alternative Energy Twenty-centimeter steel helical spring pairedCurved side single D cell holder in premium unbreakable plastic, sized so the heavier D cell stays seated when student built circuits are picked up, tilted, or carried between stations.