What's the best electric grooming shears for a small cat with long fur?

Wahl clippers has a set that they sell in their veterinary line that is light weight, cordless, very quite and fast (I’ll have to look when I go in on Monday, I can’t remember the model name). My dad has a bitch of a fractious persian that I shave down for him. I can do the whole cat – restraint and clipping- in about 90 seconds (when properly motivated).

I have clippers made for long-haired cats, and they were a waste of money. It is almost impossible to clip soft, silky fur.