Halda TwinMaster is in effect two TripMasters combined into one case so you can use one meter for the day's or section's total mileage and the other for each interval between road book instructions. There are two versions of the TwinMaster. Earlier one has a metal outer case. The later one has a plastic case and minor internal improvements.

All of the installation and operating instructions for the Halda TripMaster on the prior page apply also to the TwinMaster.

This Halda TwinMaster 911 rally computer appeared on German eBay 07November2010.