It's going to be small and thin, but it will look like a PC's hard drive, only thinner and smaller. Many have a big white sticker with black writing on it, but that may not be, depending on what kind of laptop you have a the hard drives they use.
What Does A Laptop Hard Drive Look Like?
Same as a normal hard drive, but smaller. Desktop hard drives are normally 3 1/2 inch diameter, notebooks are 2 1/2 inches.