The Rex Guinea Pig

The Rex is one of the largest breeds of guinea pig and is noted for its cuddly and affable nature. They are generally very laid back and a good choice if you want a "lap pig" or one that is particularly cuddly, docile and friendly. 

The fur is coarse and wire-like and the whiskers are crinkly. The Rex is often confused with the Teddy as they look very similar with their plush fur type. There are methods of telling them apart however; the Rex will have crinkly whiskers while the Teddy has whiskers that are longer and straighter, and the fur on a Rex is far more coarse to the touch than that of the Teddy.
The nails on the Rex, especially on the rear feet, are usually thicker than those on other breeds and they tend to grow slightly quicker too.

 This only makes nail clipping slightly more awkward if you are using human nail clippers as the thicker nails won't always fit between the blades. Using puppy and kitten nail clippers, with a larger notch in the blades and available from your vet or pet store, is my recommended method for keeping their nails trimmed.