The CFA Sphynx breed standard states:
EARS: large to very large. Broad at the base, open and upright. When viewed from the front, the outer base of the ear should begin at the level of the eye, neither low set nor on top of the head. The interior of the ears is naturally without furnishing.
COAT/SKIN: the appearance of this cat is one of hairlessness. Short, fine hair may be present on the feet, outer edges of the ears, the tail, and the scrotum. The bridge of the nose should be normally coated. The remainder of the body can range from completely hairless to a covering of soft peach-like fuzz whose length does not interfere with the appearance of hairlessness. This coat/skin texture creates a feeling of resistance when stroking the cat. Wrinkled skin is desirable, particularly around the muzzle, between the ears, and around the shoulders. There are usually no whiskers but if whiskers are present they are short and sparse.
One of Dragonheart's Ears:
One of Merlin's Ears:
So, as you can see from the breed standard, Sphynx are not totally hairless. In accordance with the breed standard, we both have normal fur on the bridge of our nose, and short, fine hair on our tails. Neither of us has hair on our feet, and Merlin has a bit of hair on his scrotum. The ears are the big difference, in terms of the amount of fur present. Dragonheart has quite a lot, as you can see in the photos, whereas Merlin essentially has none.