The2Tails Mermaid Tails For Swimming With Monofin Scale Edition Swimmable Mermaid Tails Tail Purchase includes: Monofin, Happy Hats (to protect the tail tips), and FREE Backpack (Pictured)!! Tail assembled and ready to be used. We use a 4-Way stretch, nylon/spandex mix fabric, which creates the perfect fit Our Monofins are 100% reprocessed plastic because we're Mermaids and we care about our our oceans! The monofin is also unbreakable. Made in the USA Check out our size chart to find your perfect fit!