It has lots of little steel pins that slide independently of each other so you can press it on a stock leaving an impression of the profile. Using this you can check to see how close you are to what you want.

Need the name.

Thanks.

Contour gauge , I think thats it .
Get em at Lowes , Home Creepo, Most any

hardware store

flinter6 out

Lee Valley Tools sells it and it is found at Profile Gauge

Here's another: Profile gauge, stainless steel

Since they are mostly (?) used in tile work (ceramic, etc.) your local tile shop should have one.

Thank you gentlemen.

what Sysephus , except you'll find them in the wood working area, especially in the crown molding area

jeffe