This part is a kind of semiconductor called 42BYG304.

Function of this product has Stepper Motor.

Manufacturers : KySan

Image and pinout :

Some of the text within the PDF file :

Fax Orders to 650-960-3875 HB Stepper Motors Step Angle 1.8°±5% Insulation Resistant 500V DC 100MO Min Insulation Strength 50Hz 1Minute 500V Min Ambient Temperature -20ºC~+50ºC Temperature Rise 80ºC Max Shaft Radial Play 0.02mm Max Shaft End Play 0.1-0.3mm Stepper Motor 42BYG/BYGH Series HB Stepper Motors Kysan # MFG# No.of Voltage Current Phase (V) (A) 1123001 42BYG014 4 8.5 0.45 Resistance Inductance (Ohms) (mH) 19 13 Holding Torque (g.cm) 1300 1123002 1123003 1123004 42BYG016 42BYG017 42BYG023-2 4 2 2 12 0.16 6.3 0.42 12 0.4 75 15 30 55 900 16 1400 36 2100 1123005 42BYG034 2 14 0.4 35 44 2300 1123006 42BYG205 4 12 0.16 75 15 1320 1123007 42BYG228 4 12 0.4 30 23 2000 1123008 42BYG023 2 12 0.4 30 36 2100 1123009 42BYG304 2 12 0.3 40 80 [ ... ]

42BYG304 PDF Datasheet Download