I absolutely love these low friction adjusters - these are pit box ESSENTIALS for anyone serious about RC. I using these on my Tamiya TRF415MSXX from day one and compared to any other tie-rods I've seen, these give the BEST performance!
They a certainly way better than the normal plastic Tamiya parts, and have the covered 'cap' design rather than the open design you see on a-lot of other Tamiya tie-rods like TT01 steering tie rods. I have actually gone round and replaced the 5mm adjusters on all the tie rods on my cars with these now! You get 8 in a pack, so that's enough to make 4 complete tie rods.
Look after these and they will last a very long time - Just pop the connectors off carefully every few runs. Then wipe down the connector and ball end to remove any dust, dirt or particles and snap back on. I can speak from experience - these will last a long time and as I said, I've replaced all of my 5mm connectors with these now!
You should be careful when you make up your new tie-rods to not damage the adjuster. They can be very tough to screw onto the rods - the best way I found was to put some padding around the adjuster then carefully grip with some pliers. I then used a turnbuckle wrench to screw the tie-rod into the adjuster. If you don't have a turnbuckle wrench BUY ONE - I've seen nice blue tie rods damaged very badly by trying to use pliers to grip it... bad idea!!