Will this water block work?

Hello,
I have an ASUS HD6870 graphics card and I want to put a water block on it, will the Watercool HEATKILLER® GPU-X³ 6870 work?

If your 6870 is a reference design (as in it looks like this) then that block will fit just fine. If it is a non-reference 6870, then you'll need to look for a different block.

Thanks for the reply but my card is http://www.newegg.com/Product/Product.aspx?Item=N82E16814121418

Sadly you are out of luck for now. Waterblock manufactures mainly aim at designing blocks for reference designs since there is the highest number of cards out there based on that one design, otherwise designing blocks for non-reference leaves them with a small market for those products since they would only work on one card.