This part is a kind of semiconductor called FMGG26S.
Function of this product has Ultra-Fast-Recovery Rectifier Diodes.
Manufacturers : Sanken electric
Image and pinout :

Some of the text within the PDF file :
Ultra-Fast-Recovery Rectifier Diodes Absolute Maximum Ratings Parameter Type No. VRM (V) I F (AV) (A) With Heatsink Electrical Characteristics (Ta = 25°C) Tstg (°C) VF (V) max IF (A) IR (mA) IR (H) (mA) Others IFSM (A) 50Hz Half-cycle Sinewave Single Shot Tj (°C) t rr (ns) IF /IRP (mA) t rr (ns) IF /IRP (mA) Rth ( j-c) (°C/ W) Mass Fig. (g) VR = VRM VR = VRM max Ta =100°C max FMG-G26S FMG-G2CS 600 1000 4.0 3.0 50 –40 to +150 30 2.5 4.0 4.0 3.0 0.5 0.05 3.0 0.3 100 100/100 100 500/500 50 100/200 4.0 50 500/1000 2.1 A FMG-G26S 5 Average Forward Current I F (AV) (A) TcIF(AV) Derating D.C. Forward Current IF (A) VF IF Characteristics (Typical) 30 I FSM (A) I FMS Rating 50 I FSM (A) 10 4 40 20ms 1 Peak Forward Surge Current 3 t /T = 1/2 t /T = 1 [ ... ]
FMGG26S PDF Datasheet Download
