This part is a kind of semiconductor called MP10.

Function of this product has Power Rheostats.

Manufacturers : Vishay Siliconix

Image and pinout :

Some of the text within the PDF file :

MP10 Vishay Angstrohm Power Rheostats 25 Watt FEATURES • • • • • • Diameter 1 9/16" [39.69mm] Depth behind panel 1 3/8" [34.92mm] Shaft 1/4" [6.35mm] diameter Rotation 300° ± 5° Weight 0.180 pounds (82 grams) Mounts on panels up to 1/4" [6.35mm] by means of a 3/8" [9.52mm], 32 bushing and hex nut • Non-turn lugs require 3/16" [4.76mm] hole, 1/2" [12.70mm] below center of shaft Model "A" shaft • U. L. Recognized, File No. E51076 RESISTANCE VALUES* TOTAL OHMS MAXIMUM APPROXIMATE STEPS AMPS DIMENSIONS in inches [millimeters] 1 9/16 [39.69] Dia. 1/2 [12.70] 27/32 [21.43] 1 3/8 [34.92] 11/32 [8.73] Knob # 552 1.0 2.0 3.0 6.0 8.0 10.0 15.0 25.0 35.0 50.0 75.0 100.0 125.0 175.0 250.0 350.0 500.0 750.0 1000.0 1500.0 2500.0 3500.0 5000.0 5.00 3.54 2.89 [ ... ]

MP10 PDF Datasheet Download