Transistor Tester DIY Kit DC 6.8‑12V with PWM Square Color Screen, ESR Volt Frequency Meter for NPN PNP Transistors, Field Effect Transistors, Diodes: Amazon.com: Industrial & Scientific
Npn Transistor, NPN Transistors Transistor Assortment for Industry for Plug Transistor for 2n3904 Npn Transistor for PNP Transistor: Amazon.com: Industrial & Scientific
ESR Meter with Case NPN PNP GM328 Transistor Tester Small Volume Resistance Inductance Capacitance Meter for NPN and PNP Transistors: Amazon.com: Industrial & Scientific