Resistance Cord designed for use with Swim Tether Swimming Systems, but can be used for many different purposes. Made from hollow core propretiary blend materials, this cord offers resistance similar to a bungee cord. Cord has two plastic clips - one on each end designed for normal use - NOT Heavy Duty or to be used for normal bungee cord utility use. All of our stretch cords are manufactured here in the US using a proprietary blend of UV and chlorine resistant resins to craft the perfect resistance cord for harsh swimming pool environments. We offer a range of cord lengths in addition to the standard 4.5, 6, and 8 foot standard sizes. All cords come with a carabiner. Recommendation on Cord Length: Pool features, such as ledges and steps, as well as the swimmer's height and reach, all play a role in determining the appropriate length for the cord. 4.5 ft cord for most swim spas 6 ft cord for use in swim spas and pools in the 12-14ft range 8 ft cord for pools greater than 14ft WARNING: This cord is only designed for boyant swimming usage for one individual at a time. This cord is not a life-saving device. DO NOT attempt to pull too strongly on cord, or it could snap or break. Use at your own will. Please contact us if you have questions regarding the use of this cord.