I just purchased a solar powered roof vent and was wondering what the best adhesive/sealant is. I went to Home Depot and found several tubes of sealant made by Henry but dont really know which to purchase.

I watched a "this old house" on Youtube and they used a tri-poly tube of adhesive/sealant to both stick the vent to the decking and to seal around the vent. I need the sealant to be black but other than that I have no preference. There are several products from Henry but I dont really know the difference.

Obviously I want this to last a long long time, so any thoughts?