This is a cheap external Bottom Feeder which can work on any Ego/Riva battery and any mod having a 510 connector. Easy to build VapeBuddy and good to vape on. Needed materials: -battery connector ego/riva -ego cartomizer connector, or 510 atomizer/cartomizer connector and a spacer - medical IV kit for transfusion - 5 or 10 ml childproof bottle - velcro tape Needed tools: - Dremel+burs+discs or saw+sandpaper+files - soldering equipment - hot glue gun Step by step guide: 1. cut the sharp part of the IV kit larger needle, remove the plastic connector from the needle, you get a stainless steel tube 2. insert the tube into the center post of the cartomizer connector 3. solder the base of the center post with the needle extending 1/3" to the atomizer end, and attach a short piece of wire 4. insert the soldered center post into the battery connector, the center posts are the same on both connectors, and by switching them over we avoid drilling the full center post of the battery connector and we use that full post on the battery side of the feeder so no juice will get to the battery. The tube must go out through the old button hole in the battery connector. Be careful not to strangle the fragile tube. 5. solder the wire to the center post of the cartomizer connector, and solder the cartimizer connector to the battery connector's edge 6. (optional) inject hot glue in the hole by the little hose Results: 7. remove the outer shell from the bottle cap (child protection) 8. drill the top of the inner cap and enlarge the hole in the dropper 9. insert the tube through the inner cap hole and the dropper, and attach another cut needle so it can reach the bottom of the bottle, or just use a longer tube than I did 10. use velcro tape to attach the bottle to the battery/tube mod as in the first picture. Happy vaping! PS: English is not my native language so please excuse my spelling.