HOME : TUBE FITTING RECOMMENDATIONS PRODUCT APPLICATION NOTICE: Tube Fitting Recommendation for Markel’s Fluoropolymer Tubing Product Line. Markel is often asked for a source of stainless steel fittings and end plugs for use in ozone and other chemical transfer applications. MEM-CO is a company that offers a line of high quality single barb fittings that provide an excellent choice. See www.mem-co.com Markel Corporation 435 School Lane Plymouth Meeting, PA 19462 610-272-8960