<br>This is great for home school making and breaking a single electrical connection circuit experiments. good for teaching basic principles of electricity & how a simple circuit works.these are great for demos and project. Easy to use and great learning tool for kids.I think practicing on an education model would definitely benefit any student. <br>These durable individual plastic d-cell battery holders can be quickly and easily snapped together to form either parallel or series connections. They can be used individually or configured in parallel. <br> screw type binding post,If you use alligator clips you might want to temporarily remove the connector knobs. <br>This Battery Holde consists of baseboard, binding post. <br>Battery Holde size:The base is 1 3/8" x 2 7/8" and when closed it is 1 1/8" high. <br>Main Color: Black <br>material: the use of high-quality copper and plastic. <br>Net Weight: 38g <br>Package Include: 6 x Battery Holder