Tritium tube 11mm x 3mm. Ice blue. Drilling 2mm pilot hole straight through and then 3mm main hole through carbon scales one side at a time. By doing one side at a time both holes ended up slightly offset by a micro amount less than 0.3mm. This was done so the tritium tube would have to be gently pressure pushed into the hole and fit tight without the need for glue. (Note: the micro offset actually worked.) After drilling I slightly sanded the hole edges with a rat nose sharpening tool (Lansky blade medic) which I used for filing serrated knife blades. Inserting tritium tube. Gentle finger pressure needed due to micro offset. Used match to push tritium tube further in to line up even on both scales. Neat finish at 1mm below carbon fiber scale surface both sides. Tritium tube is above lanyard hole. 4mm gap between carbon fiber scales. Tested in a darkened room and works brilliantly. Tritium blue dot on each side of the knife and a 4mm blue light on the back of the knife and when flipped over two small blue dots each side of the blade when the knife is folded. More photos There is enough room to fit two more tritium tubes. Just got to chose the colors.