I bought this from Amazon for less than $20 and it included a case that required some assembly. I’ve seen this same board and similar on eBay for less than $10. It is quite handy for identifying random components and for checking their values. It runs on a single 9V battery. You place the leads of the part under test into the ZIF socket, or using a set of clips leads. Press the single button, and within a few seconds, it identifies the type of the part, as well as relevant values. So, for a capacitor, the capacitance; for a resistor, the resistance; for a diode, the forward voltage drop, and which lead is the anode and which is the cathode. And so on, for many different component types.