Pretty much as already discussed but allow me to disagree slightly. I would say that they are useless UNLESS they are stripped and rebuilt once in a while. So if ,like me, you enjoy solving mechanical problems and your time is your own , its not really an issue. Some people just like to ride and I get that, but others , like myself, consider time spent with the spanners to be an equally satisfying aspect of the biking experience. Yeah I see others have mentioned the same but just another wooden spoon in the broth. I spend all my time at work spannering and fixing the same things over and over due to poor truck design and driver abuse so for me I will be sourcing some ‘better calipers’ Rather than over hauling mine again like I did when I bought the bike. And for the price I paid for all the seals ect I could have waited for a used pair of calipers to pop up for only a few quid more. If I were the op just cut out the middle man (also the 6 pots are a pig to bleed)