Another use is in conductive paints for antistatic coatings and electromagnetic shielding. Conductive antistatic bags are commonly used to protect such components. For example, antistatic additives can be added to help polypropylene surfaces resist dust and dirt. Indium tin oxide can be used as transparent antistatic coating of windows. Dust attraction may be reduced by treating insulating surfaces with an antistatic cleaning agent. Sony's rewritable media are spin-coated, using a scratch-resistant acrylic and antistatic coating. It is odourless, insoluble in water, biodegradable, non-allergenic, antistatic and virtually nonflammable. Humectants are sometimes used as a component of antistatic coatings for plastics. Some hydrophilic grades of PEBA are also used for their antistatic and antidust properties. It is used as an antistatic additive agent in automobile fuel caps and pipes. In addition to being used as a surfactant, hydroxysultaines are often used as antistatic agents. It has uses as a foam booster, viscosity builder, and an antistatic agent. The compounds can also act as antistatic agents, which helps to reduce frizzing. Some ground mats allow you to connect an antistatic wrist strap to them. Polyquaternium-7 is used for its antistatic and film forming properties.