Designed especially for Pro Spar & Pro Comp 19’s; although, also adapted for the RET370, RET75, and RPS16 or RPC16 sticks. Attaches to the skin with a Gibian Loop and 2 split rings which are included. Adjust by turning the knurled aluminum head counter-clockwise. The long nylon screw is actually concealed inside the stick that you are lengthening. See matrix for sizes. Dale Vanderhoof, of California, loves these fittings. He uses them with PS19L sticks to make his 9’ diameter “Rasta Flowers”. He is the guy that modified my original one split ring fitting, converting it to a two split ring fitting.