Scissors are hand-operated shearing instruments. They consist of a pair of metal blades pivoted so that the sharpened edges slide against each other when the handles (bows) opposite to the pivot are closed. Scissors are used for cutting various thin materials, such as paper, cardboard, metal foil, thin plastic, cloth, rope, and wire. Scissors can also be used to cut hair. Hair-cutting scissors have a specific blade angle ideal for cutting hair. Using the incorrect scissors to cut hair will result in increased damage and or split ends by breaking the hair. Food scissors, also known as kitchen scissors, are for cutting and trimming foods such as meats. Hair-cutting scissors and shears are functionally equivalent, but the larger implements tend to be called shears. A large variety of scissors and shears exist for different specialized purposes. Modern scissors are often designed ergonomically with composite thermoplastic and rubber handles which enable the user to exert either a power grip or a precision grip.