The Housings are a steel investment cast for a longer life, Gland Nuts are Heat Treated for a longer wear, Rotary Sleeve is Heat Treated for longer wear and milled with (2) flat areas that are machined on the rotary sleeve for wrench-tightening, Backup Ring is Nickel plated to prevent rust, Zerk fittings are installed to lubricate for longer wear, All parts are interchangeable with TM® manufactured swivels.