Flat Wicks for Most Oil Lamps High grade cotton for a clean burn and fast fuel. Our selection is unsurpassed - we have a wick for almost any flat wick lamp ever made. 3/4" wide. 6" to 8" long. Comes in packs. Cotton. Replacements for oil lamps and lanterns. Need help figuring out which wick to use? Turn your burner over and measure the width of the wick channel.3/4" wide: A common size often used in #2 Burner because it's an easy (loose) fit.