While I was introducing the splendid Aero fuel caps it became clear that there was a demand for a lighter and cheaper assembly so we developed the SPRL series.
It is used by most light sport aeroplanes and because it is so simple we have been able to hold an unchanged price for over ten years. The range includes the “S” Standard cap and the ” L” lockable version.
We have two flanges – the “G/S” threaded version, (same thread as the Aero caps) and a ‘universal’ red flange that can be glassed in to a composite skin, or riveted under a metal skin.
Note that the edge clearance in a riveted installation is small- but as the flange is massive most people think the edge distance is fine. Give a full clearance on the thin skin and accept reduced margin on the flange.