The vintage VW dash mileage counter has a magnetic base and the size is about 4x3cm.

It is an accessory that you can use to note the mileage of the next fuel fill up or oil change.

After the tank is filled with fuel, you just roll the wheels on the counter to match with the speedometer mileage and you are on the way. You then compare your mileage to it and you know how far you have driven. After about 350 kilometer with your VW bug, it will remind you to fill fuel up again. It is a must have in a vintage car without a fuel gauge. No more notes...

You can call it vintage dash mileage counter or:
vintage mileage counter
KM kilometer counter
mileage counter
mileage minder
kilometre minder
oil change reminder
small mileage counter
manual dash remind counter
dash trip counter
fuel reminder
trip counter
manual odometer
trip odometer
fuel odometer
KM Boy
gas boys
gasboy

The first picture shows the Vintage dash mileage counter in an German Autozubehoer Katalog Halt from 1965.

Below you see lots of variations of the miles counter sold in in German between 1953-1970.

Vintage mileage counter fuel VW T1 VW T1 Bus with vintage mileage counter
Vintage mileage counter fuel kilometer, oil change and departure reminder in white and new old stock
KILOMERK KILOMERK
Tankfix Oelwechsel oil change reminder
Tankfix Oelwechsel oil change reminder
Tankfix Tankfix
Tankfix mileage counter VW Gute Fahrt 07-1963 Tankfix
Tankfix Abfahrt KM Miles Gauge for VW Split Oval Beetle Tankfix Abfahrt KM Miles Gauge for VW Split Oval Beetle
Tankfix Abfahrt KM Miles Gauge for VW Split Oval Beetle Tankfix Abfahrt KM Miles Gauge for VW Split Oval Beetle
Tankfix Abfahrt KM Miles Gauge for VW Split Oval Beetle Tankfix Abfahrt KM Miles Gauge for VW Split Oval Beetle
KILOMETER-BOY KILOMETER-BOY
white, ivory aged Kilometer Boy white, ivory aged Kilometer Boy
Mileage Fuel KM remind counter 1968 KILOMERK
Vintage kilometer counter black VW T1 VW T1 Bus with black KM counter
kilometer, oil change and departure reminder in black and new old stock
VW T1 Bus with black mileage counter
Dash fuel gas remind counter TANKEN
ABFAHRT, TANKEN
Kilometer Boy abfahrt tanken 1964 TANKEN, ABFAHRT, OEL
vintage Tankfix KM Counter 1961 Tankfix
KILOMETER
An old point of sale display. The cool display is made of metal, so the store owner could put new magnetic miles counters easily.
Oellux oil change reminder VW Oval This is the rare Oellux. The Oellux is made of metal and a very early mechanic oil change reminder. It can be mounted on the VW Oval bug steering column.
Oellux VW Oval Bug 1953 with Oellux fully loaded - WOW
Oellux thumbwheels, the good old quality
Oellux in Kraftfahrzeug Zubehoer 1957 Oellux in Kraftfahrzeug Zubehoer 1957
DBGM Chrome Kilometer Counter in my 1959 VW bug DBGM Chrome Kilometer Counter in my 1959 VW bug
DBGM Chrome Kilometer Counter DBGM Chrome Kilometer Counter
Chrome Kilometer Counter in 1965 VW bug Chrome Kilometer Counter in my 1965 VW bug. The first owner put it in...
Made in Germany kilometer dash trip counter in black / silver with a sticker on the rear side.
VW T1 Bus dashboard with a made in Germany kilometer trip counter in black / silver.
Made in Germany kilometer dash trip counter in black with a sticker on the rear side.
VW T1 Bus dashboard with a made in Germany kilometer trip counter in black.
magnetic KM dash trip counter
VW T1 Bus dashboard with magnetic KM counter.
magnetic KM-Merker in parts catalog
VW T1 Bus with magnetic km dash trip counter
magnetic KM MILES dash counter
Volkswagen T1 Bus dashboard with magnetic KM MILES counter.
meko Meko made in East Germany (DDR) KM counter. Period correct and nice only in a Trabant.
Vintage KM MILES counter with matching photo frame Vintage KM MILES counter with matching photo frame
km-miles Thermo in parts catalog