WARNING - this is a work in progress.
This is designed to let you run your ES120/ES121 electronic screwdriver by depressing a lever on the side allowing for finer control when holding the screwdriver at the tip.
Print it using 0.1mm layer height and use a M3 nylon screw/nut to hold it in place. The band will be a snug fit on the screwdriver when nipped up.
Use an emery board/sandpaper on the button depressor under the lever until the lever presses the button at the right position for you. I removed a lot of material so that the button is depressed just before the lever touches the screwdriver so it can't exert too much pressure on the switch.