API Matrix Retainer - Ivory - Great for difficult, complicated fillings. The matrix holder has a claw at one end with two flat semicircle arms having a pointed projection at the end. On the other end of the matrix band holder, there is a screw which when tightened, brings the ends of both the claws closer to each other. Band used with this matrix has one margin slightly projected in its middle part. This projected margin is kept towards the gingiva on the side of tooth preparation. The band of suitable size is selected and encircled around the tooth. API Matrix Retainer Tofflemire - The Universal (Tofflemire) matrix system is used in Class II restorations. The primary function of the matrix is to restore anatomic proximal contours and contact areas. Used in Class II cavity preparations or cavity preparations involving one or two walls. Advantages : Establish Proper Anatomic Contour Restore Correct Interproximal Contact Relations Prevent Gingival Overhangs