Three o-rings for the final drive of the Honda Valkyrie 1997-2003 GL1500C GL1500CD GL1500CF GL1500CT
These o-rings are made of a very tough polyurethane. The big skinny o-ring is the one that wears out very rapidly if nitrile rubber material is used. Red Eye uses a thermoplastic polyurethane to give this o-ring some endurance.
Red Eye is making these o-rings available because the Valkyrie is not reliable with nitrile o-rings in the final drive.
There are endless tales of ruined final drives, where water washed away the moly grease from the splines. This is partly because third parties provide incorrect "Dash Number" o-rings of inadequate thickness, and partly because the final drive rapidly abrades through nitrile rubber. Polyurethane is going to last a lot longer, and Red Eye is even supplying these o-rings in the correct metric sizes. If you get your final drive o-rings from some third parties, you'll get 0.070" thickness for the big skinny o-ring. The spec is .080"=2mm, and 0.060" thickness lets water in. If you put the 0.070" thick o-ring in there, it is already 65% worn out, volumetrically. See second picture. This foolish swap of sizes encourages final drives to leak water in to the splines, long before it is time to buy a new rear tire. Tire replacement time is when you'd naturally inspect and regrease the final drive splines and drive shaft splines.
You can find more information on www.valkparts.com. For example, the installation instructions are downloadable there.