Calibration is automatic every time the scale is switched on. A calibration weight is also provided (and recommended for use approx. every three months).
It takes two AAA batteries and include automatic switch-off to protect battery power.
The Clearaudio uses good old AAAs meaning that spares are never far away, wich for me gives it the edge.
Roy Gregory, HiFi
... this is about as near to the perfect product as you have any right to expect.