Looking at buying a second hand trip computer off E-bay. There are several for sale but some seem to have the white writing on the face and some dont, is this just an illusion or is there differences in trip computers. I have checked mine and the writing is on the inside so it cant wear off so I am thinking its just the reflection from the camera flash hiding the lettering.

All the writing is based from the inside, the button is clearish.
The remainder is painted black/brown etc. Usually the other color wears off and exposes more white/clear.