Roller type with computing function Hold memory function Auto power off, unit & scale values – KP-90Display :10 Symbols Symbol Batt E SCALE,MEMO, HOLD, cm2, m2, km2, ft2 acre,Transverse direction roller movement unlimited Precision- within +_ 0.2%,Power Supply- DC, Internal rechargeable, battery. chargeable with AC adapter Operating Time- around 30 Hours using Battery Display- LCD 6 digit,Measuring Range- 325mm width – roller rotating length 30m.