The Avocet line claims to have a more accurate sensor system, but the real reason I stayed with them as a brand was I already owned a unit.
The routine went like this; mount the original unit for altimeter purposes, like it, get another sensor and mount it to the Elefant, get the speedo/altimeter stolen.
Only route was to get another Avocet or start all over with new sensors. Calibration shows the stock speedo is 10% high, odometer is about 5% high.