The type of rain head required will depend on a variety of factors including:
1. The type of pipe system you have (either "wet" or "dry"). In "wet" systems, a mosquito proof screen of no more than 1mm must be fitted to prevent mosquitoes breeding in water in the pipes.
2. The space you have to work with. It is important to install the rain head and still maintain adequate fall of the pipes to the tank. This will ensure that water flows freely to the tank and does not 'back up' in the pipes.
3. The amount of rainfall for the area and the extent of leaf and debris build up in the gutters.
4. Personal preference for a particular rain head design.