Be careful with carbon posts on a mountain bike. I am a big carbon fan, huge weight weenie. I still won't risk a carbon post on my mountain bike. I've seen too many people break them in races. If you can get by with a 330 mm post go with a Thomson Masterpiece. Only 192 grams and very durable. If you need longer than a 330 check out Extralite, I just ordered one of their posts. You can get the 400 mm for about $180. It only weighs 178 grams, I can't wait to receive it!