C-Line Magnetic Cubicle Keepers Display Holders, 8 1/2 x 11, Clear, 2/Pack Magnetic Cubicle Keepers? clear polypropylene insertable holder with black backing. Attach phone lists, photos, certificates and more to file cabinets, desks or any metal surface. Use horizontally or vertically. Clear polypropylene insertable holder with black backing. Two holders per pack.