There have been four versions of the Cadar electronic micrometer...
The original digital electronic micrometer, dating back to 1979, has a purple coloured LED display and a single yellow or red button above. There are no buttons below the display.
Micro 2000 has a square two pin battery charger socket in the back door and no data output. It uses a 4 cell 4.8V NiMH battery (NiCd supplied with the original instruments).
The first Microstats have a grey LCD display with black numbers, a yellow button above and 3 small grey buttons, Z, C and S, below the display. If you switch on a Microstat while holding down the S button (ie. hold down S and press Z) then the display will show you its version number, here "Sys 1".
Microstat version 1 has a square two pin battery charger socket in the back door just like Micro 2000 but uses a different battery - a 3 cell 3.6V MiMH battery. Do NOT try to use a 4 cell Micro 2000 battery in a Microstat as it may cause permanent damage.
Second generation Microstats look very similar to Microstat version 1 with a grey LCD display, a yellow button above and the grey Z, C and S buttons below the display. If you switch on a Microstat while holding down the S button (ie. hold down S and press Z) then the display will show you its version number, here "Sys 2".
The most obvious physical difference is that Microstat version 2 has a round 6 pin connector for battery charging and RS232 data output. Microstat v3 uses a 3 cell 3.6V NiMH battery slightly smaller than that from version 1 and it is not possible to insert a Micro 2000 battery in a version 2 Microstat.
Microstat version 3 has the same LCD display as the earlier Microstats and the same yellow and grey buttons. If you switch on the Microstat while holding down the S button (ie. hold down S and press Z) then the display will show you its version number, here "Sys 3".
Microstat version 3 has a round USB and battery charging connector similar to the version 2 Microstat but this time it has only 5 pins arranged in a + pattern. Microstat v3 uses the same 3 cell 3.6V NiMH battery as Microstat v2.