Pair of brackets to mount original GTAm ATE front brake calipers to standard 105 series uprights. You must cut off the caliper mounting lugs on a standard upright and then bolt this bracket on.
Note that a 1300/1600 upright has a slightly different camber angle to a 1750/2000 one so you should use a 1300/1600 ATE upright for a wide body 1300GTA and a 1750/2000 upright for a 1750 GTam.