Ouch and bugger! Have you hit it on anything or is it an old injury revisiting? Might be an idea to get to A&E, Dave. Hope this doesn't scupper your...
The cheapy open frame chronos with exposed LED's do the job but some only read in m/s but the conversion is easy. My advice if you get one is to buy...
I wonder if it might have been more interesting if you had of said what is the best and (why it's the best) to see if there was any real reason a why...