Made from a 30 year old ceramic "memory chip." This design has an off centered microchip with tiny gold wires that connect the microchip circuitry and surface mount to the leads. State of the art in the early 80s, this chip is amazing. Design geometry includes an ap protector from another memory chip and a gold plated washer. Circuit size 5/8"w x 1& 3/8"h. Gold plated alligator clip.