Scales in this range all measure in 0.1 gram increments up to the maximum weights stated. All scales are supplied with batteries for operation but they do not include calibration weights. Calibration is not generally required unless the scale takes a good knock but we do recommend keeping a 50g or 100g weight on hand so that you can place it on your scale from time-to-time to check its accuracy. While many pocket scales state on the pack that they offer an extended warranty, this is generally only valid or worthwhile for residents within the USA. All digital scales have a three month warranty with us.