Keep your lamp burning brightly. This tubular wick fits Rayo Junior Oil Lamps.7/8" ID. 1 1/2" W (when flat). 6"L. Cotton. What is a tubular wick? This wick looks like a flat wick, but the center is hollow. When you thread it through the burner, the wick forms a round shape. Just like flat wicks, tubular wicks only work with certain lamps and burners.