A caliper for measuring the internal distance between different objects.  Ideal for petanque and boccia. The resistance when pulling out the pins can be adjusted using the screw.  The screw may be a little stiff to turn, but this ensures it doesn’t come loose easily.  

Things to bear in mind

• Print using Brim, as they are narrow and may otherwise warp. 
• Leave it on the plate until the plate has cooled down. Otherwise, there is a risk that it will bend. 
• Make sure to keep the nut straight in relation to the screw, so that the threads do not strip.