I use a $10.00 pocket watch that I bought a number of yrs back from Wal-Mart. The cover keeps the glass covered so no danger of that breaking, the chain doesn't wear out like a leather wrist strap, its battery powered and it even has the date of the month included. It looks something like this but in silver not gold color, and it has a slip on catch (for attaching via a belt loop).
http://www.railwayshop.com/daylight/j3131.jpg