These are collectors, used to collect geoms. Can only be placed in the radius of your other collectors and if not in the radius of an enhancer, they will degrade over time.(Click on these to heal them)

These are turrets, used to destroy enemy enhancers and collectors. Can only be placed in the radius of your other collectors and will start slowly dying if not in radius of any.

These are enhancers, used for upgrades. Can be placed if its radius does not overlap with the radius of another enhancer. The upgrades from top to bottom are,
upgrade collector radius
upgrade money made from one geom
upgrade rate of fire of turrets
upgrade radius of turrets
(note. applied to the collectors and turrets in the radius of enhancer)