Converter Ferrules, sometimes called PINS or PINGS (for "Plug-in Skinny" and "Plug-in G-Force"), are ideal for connecting two spars with different diameters together. Their most common use is for connecting wrapped tapered spars to straight pultruded spars. They can also be used as internal or external plugs that protect the end of carbon spars from being crushed. Precision made out of a hard durable nylon, Converter Ferrules are available in 5 sizes.