The Copal UA-251 is a small automatic blood-pressure monitor, which relies on a piezo-electric microphone for detection of Korotkoff sounds. The Dinamap 1848 automatic monitor uses the oscillometric method for blood-pressure determination. When compared with the Hawksley random-zero sphygmomanometer, the Copal UA-251 recorded higher systolic blood-pressure, with this discrepancy widening at the upper end of the systolic pressure range. The agreement between these machines was reasonable for diastolic blood-pressure. The Dinamap 1848 had a tendency to consistently over-read systolic and under-read diastolic blood-pressure compared with the Hawksley sphygmomanometer, with median differences of 7 mmHg and -2.5 mmHg respectively.