This "original" Incra jig is the most basic of this portion of their product line. The body consists of two identical plastic parts -- top and bottom. One of these, let's call it the bottom, has an Imperial scale attached. I suggest that if one wants to use these for metric applications, that one attach a metric scale on the other, or top piece such that it can be used for either standard by simply exchanging the notched racks -- of course, you will also need to flip the unit upside down...

This model has about 8" of travel, which is more than enough to handle those cuts that are narrower than the guide rails.

Incra's Ultra and LS models offer a means of fine adjustment, but this original jig does not -- well, not a calibrated adjustment anyway. With this model, any fine adjustment (as in zeroing out) is accomplished by loosening the screws that retain the racks, adjust and re-tighten. This lack of calibrated adjustment between notches (1/32" or 1mm) does essentially limit this jig, but I find it a workable solution for this application.

Enjoy,
Corwin