Kee Klamp Key Clamp Fittings Key Clamps is the original clamp on the market. It was invented by George H.Gascoigne and his team in 1934. All others fittings are just cheaper alternative copies to the original Kee Klamp Key Clamp Fittings Key Clamps.
https://keesystems.com/product-category/fittings/kee-klamp/