This lid is the same lid we include with our 8 gallon conical fermentors. This thing is heavy duty and has one 3" and three 1.5" Tri Clover Compatible ports.

The 3" port is great for dry hopping. Recently people have been adding a sight glass to one of the ports to purge the hops before dumping them in. This helps reduce oxidation in the finished product. Having two 1.5" ports means you have options for what you want to add to the lid. A good setup might include a PRV for pressuring the tank and a barb for a blow-off. By using standard TC ports on the lid it gives you the freedom to customize these however you want