Originally Posted by nhdoc

Does anyone know if the rings that are in them when new are round or square in profile? I have an old line here which has o-rings on it, when I pulled one off it is surely not round, but I cannot be sure it wasn't round when it started and got flattened. A standard M8 metric ring will fit and may have been what this one was to start out but it got flattened out over time and adapted to the square channel it fits into.