Pre-fold diapers are often referred to as old school cloth diapering and remain a very economical option often being the least expensive. They are generally rectangular in shape though there are some square ones on the market. They are divided lengthwise in 3 sections with the thickest being the middle which requires the most absorbency. They can either be enclosed in a Velcro or snap fastened waterproof cover, or can be done up with Snappi fasteners or old fashioned safety pins.