Casual wear, be yourself.
Answered - Service Technician (Former Employee) - Burlington, ON
Answered - Technical Specialist (Current Employee) - Vancouver, BC
Answered - Service Specialist (Former Employee) - Calgary, AB
I was told by one of their employees to wear comfortable clothes - I had no idea what exactly he meant as he wasn't specific so I dressed in a business casual attire and so did most of the applicants as well.
But it wasn't needed. Dress you but dress according to the context.
Answered - Product Zone Specialist (Former Employee) - Toronto, ON