Caliper to hub set screw  for two calipers.M12. Now upgraded to 10.9 spec .
Sold as a set of 4 (enough for 1 car) these correct spec flanged head screws replace the O.E. one as they will inevitably be rusty and the heads rounded, the impact gun brigade are the culprits! It's difficult to get them torqued up correctly with rusty threads and rounded heads!
Some workshops use a 8.8 spec screw which I wouldn't recommend when you can purchase these higher spec screws for nearly half the price!
Once removed they should be disgarded IMO for safety's sake. If you are having your brakes overhauled buy a set and give them to your garage, they will be impressed! It's a small price to pay for safety and peace of mind. Always run a M12 tap into the caliper threads to clean them before fitting!! This will allow the correct torque to be achieved. 
  Set of 4 for only £2.95 plus vat (£3.54) Or look on some other MG sellers Ebay and pay £9.45 for two!! Don't get ripped off!!