The two vertical brass tubes can be moved along the plastic slider bar to adjust the final rest position of the switch blades and the brass tubes telescope inside of each other to suit the depth of your baseboards. The adjustable components allow the switch blades to just gently touch the stock rail, this reduces wear and tear in the long run. The dropper wires are a snug fit in the tube (.3mm ID tube with .288mm dia wire) and is not soldered or glued, this stops any twisting of switch blade tips when throwing the points over. Both switch rails are individually adjustable, to make up for any misalignment when fixing the Exactocale base to the baseboard. Trying to put screws into wood to an accuracy of 5 thou can be a bit tricky at times.