Fine coiled wire connections to terminals mounted in rubber bung sealing the Glass jar. A 15cm. Dia. electric bell also suspended on rubber cord in bell jar. For use on pump plate not less than 15 cm dia. electric bell operating on 4-6 volts AC/DC suspended on rubber cord in bell jar. Fine coiled wire connections to terminals mounted in rubber bung sealing the jar. Size 20 x 10 cm.