I got a fairly good digital all metal calipers that cost around $40 at Fry's Electronics stocked in a near by store. It is the General Brand, not USA made, but I feel of good quality that it works fine.
It has a button to read on the LCD screen: Metric Millimeter in decimal form, and Inch in decimal form, and Inch in Whole / Fraction form. Additionally you can look at the slider and try reading the non-LCD readout.
At an REI store I got a 15mm cone wrench that was of two that were in that size. It was the thicker metal one still only about $10.
HF I sometime get good luck and sometime bad. I'm wary of places that always sell extra warranty.
Home Depot and OSH and ACE hardware are other places I look for tools.
See Park Tool 13mm to 20mm sizes
Removing info on link prior posted as FB and Yelp have a lot of bad reviews. I'd buy ship to store if and only if free and no risk of having to pay shipping or return shipping if I were real careful.