These counter meter are mainly used for measuring length, it is widely used in textile, printing and dying, paper, vinyl, artificial leather ect. Turned the button on the side to adjust the digit to zero, easily used and accurate, It can work from the temperature –20 to +60 degree. Diameter of wheels: 1m 106.2 +-0.05mm Also yard is available. MODEL: J94F: STEEL COVER & WHEEL, FIRST DIGIT SHOW 1M,(3circle/M). JM325: PLASTIC COVER & WHEEL, FIRST DIGIT SHOW 10CM,(3circle/M), Steel wheel available. J96F: Steel Cover, direction same with wheel. 0-99999M JM316: Direction Same With Wheel, 6 digit, 0-999999M.