General description For use on most petrol engines with a 14mm spark plug thread, the Laser Tools Top Dead Centre Indicator 2833 provides a clear and simple indication when the piston is at its highest point (TDC). It is designed to be used in conjunction with a dial test indicator. Technical specifications Shank diameter: 16mm Overall length: 152mm Material: Low carbon mild steel with added lead (230M07PB) O-rings: EPDM & Nitrile Other information Made in Sheffield