WHAT IS IT? CRAFTSMAN MAGNETIC TAPE MEASURE MARKING GAUGE - FREE SHIPPING

Description

Hi.
Free Shipping in the US.
Here is a CRAFTSMAN MAGNETIC TAPE MEASURE MARKING GAUGE.  Appears to be in unused condition.  I can't figure out what this accessory is for. If you know, let me know. Has 2 sharp pins under the clear cover.  Magnets to hold on to tape measure.
Please see picts or ask questions.
What else can I say? See picts or ask questions for more on condition. Pictures are of the actual item you will receive.
Not Happy? Return it.
What you see is what you get.
Check out my other auctions for who knows what else.
Thanks
Jeff