The first washerless faucet, a ball faucet has a ball-shaped cap above the base of the spout, with a single handle on top. Beneath the rounded cap, a slotted plastic or metal ball with slots or chambers controls water flow and temperature. Repairs are more common for this faucet than for other washerless types, most often because of worn inlet seals or O-rings. Turn off the faucet's water supply and, with a wrench, unscrew the faucet handle or remove the handle set screw and lift off the handle. If the handle has been leaking, just tighten the adjusting ring.
If the spout has been leaking, use pliers to take off the adjusting ring and cap. Remove the cam, cam washer, and rotating ball. With needle-nose pliers, remove inlet seals and springs. Cut off the O-rings with a utility knife. Inspect what's worn and replace accordingly, or replace all parts using a replacement kit. Reassemble.