Premium Single D-Size Battery Holder with Curved Sides Physics_Alternative Energy Complete 12-piece simple machines set

Complete 12-piece simple machines set covering inclined plane

Used to supply rechargeable DC power for circuit experiments

the shared mass isolating volume and density as the distinguishing variables across metals and polymers

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

Premium Single D-Size Battery Holder with Curved Sides Physics_Alternative Energy Complete 12-piece simple machines setCurved 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.