Sinclair Custom Type B Drop Tubes are clear acrylic so you can observe your powder charge as it drops. Each drop tube is fitted with and aluminum sleeve to insure a perfect fit in your powder measure or drop tube adapter. Our .22 caliber and up drop tubes are available in 3/16" inside diameter and 4 different lengths. The longer lengths are great when you are trying to get more powder in a high fill case, especially when using longer bullets. Type B Drop Tubes will fit Lyman, Dodd, Bruno and older Sinclair/Culver style powder measures directly, no adapters are needed.