Polyacetate or polyester strips. Also called Mylar or celluloid type.
 Transparent strips.
 Measurements: 0.05mm. thick, in bands of 10 mm. width x 10 cm. long.
 Its main function is provided in restorative dentistry, where it allows the nonexistent wall or walls of a cavity preparation to be formed.
 It is generally used in the preparation of composites that affect a proximal face.