I just bought a Sunwayman R20A. The packaging claims IPX-8 waterproofing, but I have doubts.
The head of this flashlight features a silver colored metal ring that screws onto the black flashlight body. The purpose of this ring is to hold the glass lens in place. I unscrewed this ring and removed it, as well as the lens. I could see no O-rings. I could see the LED, now exposed to the elements.
This arrangement hardly seems IPX-8 waterproof to me: silver ring clamps glass lens onto black flashlight body. No rubber or plastic in sight.
The flashlight arrived with three spare O-rings: two small and one large. The small O-rings fit the tailcap. I tried pushing the large O-ring onto the head of the flashlight head in several ways. In no case did the final assembly look quite right.
I emailed Sunwayman for support. They explained it for me. The O-ring lives UNDER the lens. I had to use a powerful magnifying glass to see it. The O-ring sits in a circular "trench" in the black aluminum flashlight body, and it is almost invisible.
I am pleased with this flashlight and I am grateful to Sunwayman for speedy and accurate assistance.