A Cog Suit is a disguise that your toon uses to make themselves look like a cog. It is only used when you infiltrate Cog HQs, and you have to earn it. Different cog suit classes are earned in different ways. For instance, you earn your Sellbot cog suit by beating the Factory Foreman in Sellbot HQ ten times, but you earn your Cashbot cog suit by completing certain tasks in Donald's Dreamland. Between 8/25/10 at 12:01 AM to 9/21/10 at 11:59 PM, non-members could have a "Rental Cog Suit" and have access to the Towers.
Cog suits can reach up to Level 50, and then you are maxed and can battle the boss whenever you want!