1) Ball cock 2) Regulator 
A ballcock (also balltap or float valve) is a mechanism or machine for filling water tanks, such as those found in flush toilets, while avoiding overflow and (in the event of low water pressure) backflow. The modern ballcock was invented by José Antonio de Alzate y Ramírez, a Mexican priest and scientist, who described the device in 1790 in the ...
A fill valve device in a toilet tank. A 'Cock' is activated by a float 'Ball' to refill tank water after a toilet is flushed.
[n] - floating ball that controls level in a water tank
ball cock noun floating ball that controls level in a water tank
the fill valve that controls the flow of water from the supply line into a gravity-operated toilet tank. It