A The typical box of disc brake pads has four pads (two pads for each side of the car). Some manufacturers will included other pieces of hardware to make sure the pad performs to its full potential. The items include anti-rattle clips, shims to reduce noise and wear sensors. Also, some brake pad manufacturers include special lubricants to reduce the chance of the customer returning with a noise compliant.
Some low-quality brake pad manufacturers do not include these items in the box so they can maximize their profit and be the lowest-priced product on the store shelves.