Many variations exist, ranging from those having no moving parts incorporated in many pocket knives to dedicated electrically-operated kitchen appliances. A common type found in many kitchens has a pliers-like handle used to clamp a cutting wheel against the can's lid and a handgrip that rotates the can to cut the lid around the rim. The first tin cans, invented in 1810, were heavy-weight containers that required ingenuity to open, using knives or even rocks. Not until cans started using thinner metal about 50 years later were any dedicated openers developed. Ezra Warner of Waterbury, Connecticut U.S. was first, in 1858, to patent a can opener. The cutting wheel can opener was invented by William Lyman in 1870. A modified design with serrated rotation wheel was later introduced by the Star Can Company of San Francisco California in 1925. The first electric can opener debuted in 1931 modeling after its cutting-wheel design.