These wicks fit my Rayo perfectly, and once trimmed and charred they work like a charm. To install, fold and slip inside wick raiser tube, leaving some extra height for trimming, reach inside with a finger and burnish the wick out against the tube wall to fill it out round, pushing the wick out into the hook tabs at the top of the riser tube. Slip the wick/tube assembly over the center draft tube and trim to the top of the tube using a razor blade. Char it a bit and it's ready for fuel. I'd give it five stars, but for the fact that it only comes in packs of five at the time of this review. That would be at least a few lifetime supplies for my purposes, for one lamp.