[Unique design]: The periodic table of elements clock is 12 inches in diameter. The right size wall clock is easy to read from a distance [Good Quality Material]: Our chemistry decor clock is made of thick acrylic, lightweight but sturdy [Absolutely quiet]: This science student clock with a quiet and non-ticking sweep movement. It provides a great sleep and work environment! [Battery Operated]: This science clock powered by a single AA battery (not included). Best with carbon zinc battery [Chemistry Gifts And Decor]: Science teacher periodic table gifts. Periodic table of elements wall art chemical clock perfect for biology classroom living room, bedroom, classroom, office and chemistry science classroom decor. A great gift for your family, friends, science gifts for adults