Here is a basic guide...
Most pole floats are split into 3 different designs; the teardrop, reverse teardrop and slimline. Each one is designed for a different purpose.
This design of float is primarily for still waters were there is a little bit of 'chop' on the water. The dumpy design gives stability and is especially good when fishing a bulk shot down the line.
Although these are the main designs of floats you will see on the shelf, recently there has been a surge of specialist carp floats available. These floats are usually very buoyant with quite thick tips to avoid being pulled under by large, heavy baits. Some are designed for fishing near the surface while others are very rugged for fishing tight to marginal snags which could damage most traditional pole floats.
Hope you find this useful! Please feel free to comment!
Check out my youtube page for more advice and videos!