This AC adapter works for my HP 635 notebook. I have used it several times as a backup when I use my laptop outside of my home on the road. It does get warmer than the original adapter that came with my laptop, but this is normal. Haven't had any problems so far.
I purchased this adapter as a backup to my original ac adapter that came with my HP 635 notebook. I travel a lot and wanted to bring a secondary adapter instead of the original (in case I lost it while travelling). I have used it several times with no problems. It does get warmer than the original, but this was expected based on other reviews I have read. Hope this helps you.