Attys are Atomizers whereas cartomizers & clearomizers are 2-in-1 ie a container with a builtin atomizer.
If you use a normal atty, you have to use a separate cartridge for your e-
juice.
Also, attys are usually 0.6ml capacity to 1.8ml.
For cartomizers & clearomizers, the capacity starts from 1m-1.8ml.
Map
tank can store 2.5ml - 5ml
juice.