Viscount - Millard - Franklin - Other makes
This Catch is 38mm and is the older style for a protector shade, it is a 2 piece security catch that locks the shade cover over the window when travelling additionally they can be used for holding down cieling hatches and windows.
They are used in replace of the old style in many different types of Caravans, Campers etc.
Made from very Durable Aluminium.