This is a simple jig that allows you to easily measure the values of two legged electronic components with your multimeter. Place your component in the middle, press it with your finger and get a value for that component. It tends to be fairly useful if you need to measure a lot of resistor values quickly, etc. To assemble it, just take the two leads of your multimeter and shove them inside of the two holes. Take your component and place it in a way that makes it touch the two leads.