And dont let people tell you that 5.1 is some kind of panacea for your brakes, a good quality 4 can be better than 5.1
Which is why (for wanting of a better example) halfords sell both a basic and a race 4 and 5.1 , with the race 4 selling for almsot double the basic 5.1 .
FWIW dot 4 bought by the litre in the car and good quality dot 5.1 by the half pint in the bike as the bike gets more of a hammering (when was the last time you had to do repeated stops from 100mph in the car?). And it doesnt do it good to be left out for years so a 250ml bottle can flush through most brakes several times a year. If you've several bikes get a vacuum brake bleeder, I can bleed my hope minis in 5 minutes with it, its awesome, just pump it up, open the nipple, and pour 30ml or so brake fluid into the resevoir.