Originally Posted by
Rides4Beer
800 is Ultegra level and 700 is 105 level, they just don't label them that way. But yeah, the only difference is weight.
the 700 cassette has a slightly different cog carrier that holds only the 3 largest cogs and uses a steel lockring. The 800 has 2 cog carriers hold the 5 largest cogs + uses an aluminum lockring. They are also completely interchangeable