The model: "Float Tube Force Fins" are adjustable and only come in one size.

The model: "Force Fin" also known as "Original Force Fin" is not adjustable and is sold in sizes, i.e. XL. The "Original Force Fin" is often used as a float tube fin. An XL size is not that large if you want to wear it with a wading shoe. A surfing bootie would give you a little more room. Check the size chart on the web site.

http://www.forcefin.com/Merchant2/me...ct_Code=FFOR52