NTE507 Rectifier Diode 50V 1A 200ns DO−41
 
The NTE507 is a silicon rectifier diode designed for special applications such as DC power supplies, inverters, converters, ultrasonic systems, choppers, low RF interference and free wheeling diodes. This device has a typical recovery time of 150 nanoseconds providing high efficiency at frequencies to 250kHz.
 
Full spec sheet:
https://www.nteinc.com/specs/500to599/pdf/nte507.pdf