This part is a kind of semiconductor called 1.5KE440.

Function of this product has 1500 WATT PEAK POWER TRANSIENT VOLTAGE SUPPRESSORS.

Manufacturers : Bytes

Image and pinout :

Some of the text within the PDF file :

1.5KE SERIES 1500 WATT PEAK POWER TRANSIENT VOLTAGE SUPPRESSORS VOLTAGE RANGE 6.8 to 440 Volts FEATURES * 1500 Watts Surge Capability at 1ms * Excellent clamping capability * Low zener impedance * Fast response time: Typically less than 1.0ps from 0 volt to BV min. * Typical IR less than 1µA above 10V * High temperature soldering guaranteed: 260 C / 10 seconds / .375"(9.5mm) lead length, 5lbs.(2.3kg) tension 1500 Watts Peak Power 5.0 Watts Steady State DO-201 .210(5.3) .188(4.8) DIA. 1.0(25.4) MIN. MECHANICAL DATA * Case: Molded plastic * Epoxy: UL 94V-0 rate flame retardant * Lead: Axial leads, solderable per MIL-STD-202, method 208 guranteed * Polarity: Color band denotes cathode end * Mounting position: Any * Weight: 1.20 grams .375(9.5) .285(7.2) .042(1.1) .037(0.9) DIA. 1.0(2 [ ... ]

1.5KE440 PDF Datasheet Download