Accurately measures seat posts head tubes bearings spoke diameters etc the park tool dc 1 digital caliper is a precision instrument built with stainless steel mechanisms and a rugged abs composite body the toolrsquos ability to measure in metric decimal inch and fractional inch make it an indispensable shop tool park tool dc 1 digital caliper features accurately measure seat posts head tubes bearings spoke diameters and just about anything else you can think of the