Zurn z6915 faucet with hydrogenerator with mixing tee the z-6915-mt battery sensor lavatory faucet shown comes complete with the faucet and a mixing tee for adjusting the single water temperature. this is a true 4″ centerset faucet for mounting into any 4″ centerset lavatory. the unique battery box includes a handy jack for optional plug-in power supply transformer for applications requiring a fully powered lavatory faucet with an integral battery backup system.