The rectangular pickups in your Fender Stratocaster electric guitar act as a microphone which transmits the sound made from the guitar to your amplifier. You can change the pickups on your guitar to a different model, and one such model is the Roland GK-3. This particular pickup is unique because it transforms the sound of your guitar into that of a synthesizer. The good news is that installing the GK-3 isn't any different from any other pickup.
Remove all six strings on your Fender Stratocaster by loosening them with the tuning pegs located on the head of the guitar.
Locate the bridge of the guitar on the body of the instrument. It is the end rectangular piece that the strings connect to. Use your tape measure to measure the height of the bridge.
Set the bearings on the bottom of the GK-3 pickup about 2mm lower than the height of the pickup. This will ensure the pickup fits under the strings.
Use your Phillips screwdriver to remove the screws on the bridge then remove the bridge. Place the pickup over the bridge-connector studs, making sure the loops at the ends of the pickup fit over the studs.
Replace the bridge and screws, making sure they are secure. Then replace the strings to your guitar.
Use your screwdriver to loosen your guitar's end pin (the piece the strap connects to) and then slide the edge of the black pickup controller into the gap between the pin and the body of the guitar. Tighten the pin to secure the controller and you are done.