ECO-16 wicks are designed specifically for natural waxes like soy wax. They provide a controlled curling of the wick making the ECO series self-trimming, which results in minimized mushrooming, soot and smoke. The ECO-16 wicks come 6 inch inches long with a 20mm base and 6mm neck, 100 to a pack. Primed with High Temp Natural wax. For Medium to Large Container 3 1/2 inches - 4+ inches. They work great for soy wax candles.