One FURminator to rule them all

I have a 95 lb German Shepherd Dog and a chubby 14 lb medium hair cat

I'd like to get a FURminator that I could use on both. Is this going to be possible? For the dog, he would need the "Long Hair" version probably, Large size. Would I be able to use that on the cat too? Or should I get a Long Hair, Medium size and just figure I'll have to brush the dog more.

I'd hate to buy 2 FURminators (they're expensive).

I have a small. long haired one for cats (it's the light purple one). it works great on my medium haired dog but is essentially useless on a long haired cat. I like the small size on the dog because it's easier to maneuver. 

Amazon has the best prices on them that I have found. Much cheaper than the big box pet stores. 

Make sure you read the reviews here on the site too. They can help you see what's best for your cat (sorry, not a lot of dog advice here   ) -
[product="18514"]Furminator Deshedding Tool For Cats  [/product]
And -
[product="18515"]Furminator Long Hair Deshedding Tool For Large Cats  [/product]