This is an acrylic keychain with a a clear snap closure and stainless steel key ring. The keychain (not including the key ring) is 1.5 inch (3.81 cm) tall and 1.12 inch (2.84 cm) wide. “Schrödinger's Cat” was a famous thought experiment in the 1930's between scientists Erwin Schrödinger and Albert Einstein. The scholars imagined that if you put a hypothetical cat inside a box with poison and a mechanism to time-release the poison, then after a certain amount of time, the cat is simultaneously both dead and alive. The cat is only decided one or the other once an observer opens the box to see. This thought experiment illustrates the issue of quantum superposition in the field of quantum mechanics.