How is the quality of alloy sprocket 10 speed sprocket? I saw at ebay, 10 speed cassette compatible with shimano, it's very light 103 grams, but the material is alloy with ceramic coated, it says, the cassette can be used up to 3000K, is it true? or may be more than 3000K, because if it's 3000K the age for me is only about 3 months or less riding.

Have any of you ever used one ?

Thanks
There are a lot of small boutique-factories machining extra-weight-weenie parts that serve three purposes:


Provide some weight advantage to very high-end racers who reached the limit of their training levels. That could mean positions in a very high-level race;
Satisfy some folks (whose population is increasing) who don't mind throwing money out the window to have the most exotic and customized extra-high-tech bikes;
Feed the Weight Weenie Contest members with lots of ways to shave weight of bikes they don't necessarily ride (but most probably take a lot of pictures hanging from scales to post online).


(ok, that was somewhat a bitter answer, but I think this is not far from the truth)

And, yes, this means 3 months of riding, then to the thrash can, for the cassette you mentioned. How can anyone afford that?!?!?!?