Silicone tubing is used to transfer liquids, air, or solids, and it is characterized by a round, rectangular, or square shape and a hollow center. Silicone tubing is crimp-resistant and varies in bend radius (flexibility), chemical resistance, wall thickness, durometer hardness, and temperature and pressure handling abilities. The clarity of silicone tubing may be transparent (clear), translucent (semi-clear), or opaque (solid), and the tubing's coloring may indicate suitable applications.