3B Scientific U21854 Electric Doorbell, For Bell Jar
Toys & Games | Learning & Education | Science Kits & Toys
show up to 2 reviews by default Electric doorbell for demonstrating electro-magnetic operation of apparatus and verifying that sound waves sound waves do not propagate in a fine vacuum (< 1 hectopascals). Open acrylic housing with 4mm safety sockets. Power supply: 6 volts AC Dimensions: 100 x 95 x 50 cubic millimeters.