The company's website was not much help regarding information and ordering, but an old-school phone call easily took care of that. If your specified rider weight is outside of the standard spring specs, the spring will be changed out accordingly. I don't have any idea if that was done in our case, as there was no further communication during the process. Don't be in a hurry — the shock took about a month to get here.
The shocks are made in Thailand and have a two-year warranty. YSS built their name as a budget shock maker specializing in the huge Asian scooter market, but reorganized a few years back to become a mainstream, mid-level, full-line manufacturer. Our model number is MZ456-275TR, denoting an emulsion gas mono shock, 275mm (10.8 inch) mounting length, "T" is threaded spring preload, "R" is rebound adjustable. So we loose the remote preload wheel on the OEM shock but gain rebound damping in a nice, shiny new shock. Cost was $426 shipped. Compare that to high-end shocks at about $750+ or rebuilding your OEM shock at about $350 parts, labor and shipping. I will be very interested to try this beauty on the road.