Description: Transistor is a basic semiconductor device that control current, which can also be used as a non-contact switch. Applicable to all kinds of switching power supply, adapter, charger, electrical products power . There are total 370 pieces of transistors in this set which will meet your basic needs. All transistors are well packed and assorted in a transparent box for convenient storage. Each transistors is clear marked so you can easily identify which type of transistors you need. The best accessories for Maintenance works, installation, student study. Specification: Material: Silicone, Plastic, Brass Color: Black Box Size: Approx. 180x100x20mm/7.08x3.94x0.79inch Type: PC817, 13001, 13002, 13003, 13005, 13007, 4N60, S8050, S8550, S9014, C945 Package Includes: 370 pieces Power Transistors Note: Pls allow an error of 1-3mm due to the difference of manual measurement.