Yes..heatsink is needed.( For $25..I took their word for it) There are channels in the heatsink..you can use an eyehook, Ubolt, or the like with nuts and washers..I used on hand eyehooks..If you want it fancy..they cell nice hangers for $10 I think. It is very easy to swap out different LEDs if you want to mess around. I think it has had some effect on flowering time, but a few more weeks will tell. These things signal the plant that it is time to begin Photosynthesis NOW..The signal just has to be "seen" according to Gromau5, so intensity is not an issue.