Full Lace Cap with stretch in the middle
This is the most common cap construction and found in most stock units. The stretch panel allows for half and inch leeway, so it will fit head sizes that are up to half an inch larger than the given circumference. Good for beginners who are unsure of their measurements. Hair can be worn up in a high pony tail and parted anywhere.
Full Lace Cap No Stretch
This cap construction has no stretch, hair can be parted anywhere, worn in a ponytail and cornrowed as there is no stretch panel in the middle. But your head measurements have to be accurate as there is no stretch with this cap construction.
Full Lace Cap with stretch from ear to ear
This cap construction is quite similar to a full lace cap with stretch in the middle, but the the stretch extends from ear to ear, stretch panel allows for half an inch leeway to fit head sizes that are up to half an inch larger than the given circumference. Also great for beginners who are unsure of their measurements. Downsides are wearing the hair up in arears above the ear may be a problem.
Full Lace Cap with thin skin perimeter
This type of material has a material called polyurethane (also known as thin skin) around the perimeter. Some have reported that thin skin seems to adhere better to their skin. Downsides: getting really hot under the thin skin, because it does not allow the scalp to breathe as lace does.