Technical SP204 No.4 Rubber Plug Stainless Screw - Nylon Wing Nut SP-204 Technical SP204 No.4 Rubber Plug features a durable rubber construction paired with a stainless steel screw and a nylon wing nut for secure fastening. Designed by Technical Products, this reliable component is engineered for use in various pool equipment parts, spas, and outdoor water features to ensure a tight seal and hassle-free maintenance. The high-quality materials provide resistance against corrosion and wear in aquatic environments. Made in the USA.