3M's popular kits are versatile assortments of flexible polyolefin heat shrink tubing used in a variety of electronic and electrical applications. Each kit is packaged in a plastic box. These kits allow the engineer, designer, or technician a selection of popular sizes and colors for small projects and prototypes. The black kit contains 102 pieces of six inch long tubing in six sizes ranging from 3/16 to 1 inch inside diameter. The color kit contains 133 pieces of six inch long tubing in six sizes ranging from 3/32 to ? inch inside diameter and seven colors. Shrink ratio is 2:1.