Inchworm Titanium Ruler keychain accessory from TEC Accessories. This nifty measuring tool features cut grooves every 1/8" up to 3", with larger cuts every 1/2" and 1". The possibilities are endless...check your tire tread depth, measure a broken fan belt or hose, check blade lengths etc. Made from 3/16" diameter solid 6AL-4V titanium. Check out the Centipede model for metric measurement. Comes in a foam-lined case with an 8.6mm diameter split ring and snap clip for attachment.