Easton's Haven Zero Setback Carbon Seatpost is only 50 grams heavier than the brand's ultra XC focused EC90 Carbon Seatpost, even though the Haven is built be to mounted on long travel, all mountain rigs that will see far more shuttle runs than leg searing uphill churns. If it's a head scratcher how a carbon post is fit for all mountain fun, the secret is in the sauce. Said ingredients include not only using carbon, but knowing where to take it away. That is, Easton uses Relief Area Design, RAD for short, that pares some of the material on the back of the seatpost, leaving a lengthwise flat strip. This is where most seatpost clamps over stress the post, especially if you apply too much force to the clamp. By flattening the rear of the post, the pinch force of the clamp is redistributed around the entire shaft, relieving any potential over stress. Easton also builds the Haven Zero Setback Carbon Seatpost with a TaperWall layup schedule. This determines that the shaft of the post that sits inside the seat tube is reinforced, but the exposed length is lightened to reduce weight. Of course, the seat clamp zone is also bolstered so it can handle all of the levering forces from the saddle. Additionally, TaperWall is a computer designed system both the layup schedule and actual application are precisely controlled so that all plies are completely smooth and void free. Voids and peaks and valleys in a layup create their own stress points that interrupt load forces and can later result in failures. And if all that sounds like mumbo jumbo, know that Easton backs this post with a five year warranty. That's not mumbo jumbo at all. That's confidence. The Easton Haven Zero Setback Carbon Seatpost is 400mm in length, and is available in the sizes 27. 2, 30. 9, and 31. 6, and in the color Matte Carbon.