Pinewood Pro Derby Tungsten Weights Five 3/8&rdquo; Incremental Cylinders (Three .5 Ounce, One .3 Ounce, One .2 Ounce) to Make the Fastest Pine Derby Car HIGH DENSITY, LESS SPACE - Tungsten is 1.7x denser than lead and 2.7x denser than zinc. EASILY TUNE FOR MAX SPEED - Multiple sizes make precise tuning of your Pine Wood Derby car easier. HIDE WEIGHTS OR SHOW THEM OFF - Cover the weight holes with wood filler for a sleek, clean look, hiding your weights. EASY INSTALL - Cylinders are 3/8 diameter (standard drill bit size) With chamfored edges, these cylinders will slide easily into your drill holes SAFE - Tungsten is child-safe, non-toxic for safe handling. No sharp edges.