The 855Heads is an old mailling-list group of Proflex riders who have created the following information for riders to keep their bikes on the trail and provide history of the Proflex brand.
Proflex was a major brand in the mid 1990's and really became a market leader in the USA with the Proflex 855, and in Europe with the Proflex 856 the follwing year.
Proflex used to have a simple numbering scheme for the bikes: 9xx and 8xx indicated top of the range bikes which were then re-used in future years as the 7xx bikes and then again as the 6xx bike. So, a 756 pretty much the same bike as the 855 that came out a couple of years earlier. The 657 is nearly the same as the 856, etc.
Proflex is no more. Proflex was a brand creaded by Bob Girvin with many unique products that lead the way in mountain bike construction and design. The designs were always striking and functional. The Girvin company was eventually bought by a congolomerate called Anthony Industries which eventually renamed itself K2 to bring together the K2 Ski, K2 Skate and K2 Bike brands in 1998.