This elegant marking gauge is really three tools in one — a wheel gauge, a pin gauge and a cutting gauge. 
The unique swivelling pin/blade chuck takes either a pin or a blade that locks in place (after extension is set) using a set screw in the end of the 4 1/2" gauge stem. The cutting blade can be set for either right- or left-handed use. The opposite end of the stem is tapped to accept a 3/8" diameter wheel cutter. 
The fence and the internal portion of the locking collet are a single eccentric brass turning. The collet fingers have just enough stem friction to hold a projection setting while you lock it in place with a half turn of the knurled locking sleeve. The 1" diameter fence is eccentric to maximize rub depth. A side benefit is that it also prevents the gauge from rolling off the workbench. 
Comes complete with a dozen spare blades, two hardened steel pins, a wheel cutter and screw, and a hex key. Extra stems available separately for those who prefer to switch heads as quickly as possible. 
Made in Canada. Patented. 
An excellent tool that is a great buy.

3-in-1 Brass Marking Gauge

3-in-1 Brass Marking Gauge, Kurser med Martin Ericsson

3-in-1 Brass Marking Gauge, 05N65.01