Reliable and durable cassette technology. SRAM's cassette performance is optimized through tooth profile and shift ramp design for quick and positive index shifting.
Great cassette, very reliable, pretty easy to clean I and live in a dusty climate between two highways and a railroad crossing. I keep buying this model every couple of years, I'm very satisfied.
I love the SRAM PG-850 cassette and I hope they never stop making it. For over 10 years I've been riding these cassettes both on my daily commuter bike and my mountain bike. They are very affordable, the chrome plating makes them look very sharp and prevents rust (a huge plus if you use a dry chain lubricant), they shift crisply when using SRAM chains, and I find them to be quite durable. Only once in these 10 years did I have one fail- I bent the largest cog on a brutal mountain bike ride (the other cogs still worked fine). The only negative thing I can say about them is that they are heavy compared to some (much more expensive) options, though good luck finding those fancy lightweight 8-speed cassettes these days. Unless 8-speed drivetrains make a huge comeback, these cassettes are likely to be the best replacement part available to us 8-speed riders.