Mini Spares genuine part, made for reliability- because the current Rover 22G2033 version are not good enough, these specials are CNC grooved for correct shape and machined for concentricity using the original type fixings to get the correct areas of heat treatment plus correct degrees of angles on specific areas from the original drawings making them similar/same as to what Rover were supplying pre 2000 in performance quality and reliability.
They are now better and cheaper than the current Rover product and we had to produce them for our 5 speed gearboxes.
This type of remote baulk (synchro) ring has been the same since 1962 but previously changed from steel on Cooper s to the current sintered type, but a steel upgrade based on the original type used on 1960's Coopers is available, see C-22A1741.
These rings slow down the gears to ensure that they mesh without crashing. They have a friction surface on them that is the first thing to engage the next gear when shifting. The height of how the ring sits proud of the cone surface indicates the wear, but the common sense approach is to replace them.