When I purchased "Early Light" she came equipped with a Navtec hydraulic backstay adjuster. This unit was a 1982 model and two years ago I had new seals installed. The unit began to loose hydraulic fluid again at the top of the unit. I took the unit to the shop that repaired it last, and I was told that the cylinder was scored and therefore any new seals would probably not last more than one season. I decided that it would be unwise to spend any more money on a 22 year old unit. When I researched the Navtec web site, I found that the new units were very different from the old unit that was on the boat. The new units had the hydraulic line routed outside the cylinder rather than internally as the old unit was constructed. Also, the new units were much longer in overall length which would necessitate shortening my backstay. My rigger suggested I look into the units built by Sailtec as they were approximately the same overall length as my old one and I could use my existing backstay without any modifications. The Sailtec units also have the hydraulic line routed outside the cylinder like the new Navtec units. I settled on a Sailtec Model 10SI and placed an order. The unit was drop shipped from the manufacturer and arrived in 2 days. The actual replacement only took 10 minutes plus an additional 5 minutes to tape over the cotter pins.