The Draper 92224 Digital Tyre Tread Depth Gauge is supplied with an SR44 battery The Draper 92224 is a digital tread depth gauge with metric and imperial calibration and conversion between the two. The clear LCD delivers easier reading, and the zero setting function allows for comparative measurement. The measuring range is 0 - 25mm/0 - 1\" with an accuracy of ±0.01mm/0.00039\". Supplied with SR44 battery. Features: Digital tread depth gauge LCD delivers easier reading Supplied with an SR44 battery Metric and imperial calibration and conversion Measuring range is 0-25mm/0-1\" with an accuracy of ±0.01mm/0.00039\" Specifications: Range: 0-25mm/0-1\" Accuracy: ±0.01mm/0.00039\"