Magnum, Formula, SX ?
There are lots of different names for the same thing, but there are also different setups.
A "Magnum" was a Hobie 18 with the first wings we made. Then we came out with lomger wings and called them SX Wings. If you have dacron sails, you have standard 18 sails and mast length. We have never sold mylar H18 sails for the standard length mast or Dacron sails for the longer mast. Mylar IS NOT available for the standard mast length.
The Hobie 18 SX is a taller mast , mylar sails and the newer longer wings.
The taller mast and mylar sails was first built in Europe and they called it a Formula 18. We built some here with sails that said "Formula" before changing the name to Hobie 18 SX and including the wings.
We also built standard Hobie 18s with white powder coated metal... and called them Hobie 18 Formulas.
Director of Parts and Accessory Sales
Hobie Cat USA