Our hour and minute hands are sold in pre-matched pairs, so all you need to be concerned with is the length of the minute hand. Minute hands are measured from the center of the mounting hole to the tip. Second hands are optional and should be the same length as the minute hand. Normally, the minute and second hand should be long enough to reach the outer most edge of the numbers or the minute track on your clock dial. Any of our clock hands can be trimmed to a shorter length. Please consider the design of the hand if you intend to trim it to a smaller size.