Whether you have a mechanical or quartz watch, outside of the watch movement that keeps the watch ticking, the watch hands are probably the most important part of a watch.
Replacing watch hands can sometimes require you to take some measurements so that you can order the correct replacement watch hands.
Measure the sweep second fourth wheel which is the diameter of the pinion that the sweep second hand will fit onto. Simply place the flat sides of your gauge against the sweep second pinion that is sticking out the farthest on your hand posts. This will show you your hand hole size and is the 1st hand removed or the last hand is attached to your movement. This dimension is only needed or used when you have a 3-hand movement.