This is one of the MOSFET types.
This is a kind of the transistor.
This post explains for the transistor K2996.
The Part Number is K2996 and the package is TO-220 type.
The function of this transistor is N-Channel MOSFET.
Manufacturers : Toshiba Semiconductor
1. Low drain−source ON resistance : RDS (ON) = 0.74 Ω (typ.)
2. High forward transfer admittance : |Yfs| = 6.8 S (typ.)
3. Low leakage current : IDSS = 100 μA (max) (VDS = 600 V)
4. Enhancement mode : Vth = 2.0 to 4.0 V (VDS = 10 V, ID = 1 mA)
1. DC-DC Converter
2. Relay Drive and Motor Drive