This part is a kind of semiconductor called 20D201K.

Function of this product has Varistor.

Manufacturers : TYEE

Image and pinout :

Some of the text within the PDF file :

Varistor Specification TYEE Varistor Varistor are voltage dependent, nonlinear device which have an electrical behavior similar to back-to-back zener diodes. TYEE series zinc oxide varistor are nonlinear resistors, consisting main of zinc oxide and several kinds of metal oxide additive. They are bilateral and symmetrical V-I characteristics curve and unparalleled large peak current capability are used for absorption of transient voltage, suppression of pulse noise and circuit voltage stabilization. Applications Features ● Surge Protection in consumer electronics ● Fast response -- industrial electronics ● Excellent voltage ratio -- telephone and telecommunication systems ● High stabilization for circuit voltage -- automobile equipments ● Unparalleled absorption for transient volt [ ... ]

20D201K PDF Datasheet Download