Mats are used for safety in gymnastics, and in training new skills. They are usually a piece of foam (covered in leather) ranging from 1.5-28 inches thick, covered in a vinyl or plastic lining. The foam ranges in density from relatively firm to very soft. Landing mats are usually blue, but can also be almost any other color. Mats come in a range of sizes, from very small mats used on the beam, to very large mats, used in the foam pits. Typically, in both competition and practice, the use of mats is mandatory. On every event except floor exercise, pommel horse and vault, gymnasts may use an additional landing mat, without deduction, which may be adjusted for distance. Types Beam pads These are thin mats that fasten around the balance beam. They are used only in training to give gymnasts training high-level skills additional protection and a wider landing space while working on the apparatus. Makeshift beam pads can also be constructed from soft mats placed over the beam surface, if necessary. Blocks Blocks are firm, trapezoid or rectangular shaped mats. They can be attached to other blocks via velcro and straps. Blocks are routinely used as step-stools for gymnasts working on the bars or beam and as practice vaulting surfaces. Crash mats Typically, these mats are extremely thick and soft, and are used when an athlete is learning a new, high-impact skill. Folding panel mats These mats are thin, firm mats about twelve feet in length. They usually have alternating color panels and can be folded, stacked and attached to other mats via velcro strips at the ends. Normally used for practicing tumbling moves, these mats may be stacked to provide a protective surface for gymnasts working on the low balance beam, or provide a means for a gymnast to reach the bars or rings. They have a history of usage in gymnastics, martial arts and physical education classes. Schools generally purchase new folding mats once every 7 years. These mats are perfect for providing a level of protection for the body from high impact collisions with hard solid surfaces such as hardwood or concrete flooring. There are two main categories of foam used in these types of mats, cross-linked polyethylene foam and polyurethane foam. Foam core Polyethylene foam Cross-linked polyethylene foam is a very solid and sturdy foam, when being used in a folding panel gym mat—it