433.92MHz Grey Back Only: Ensure your original remote operates at 433.92MHz and has a grey back. Not compatible with Marantec Digital 868MHz remotes with black back. Not compatible with Marantec Bi-Linked series. This remote is a replacement for Marantec 433.92MHz Multi-Bit remote controls. Compatible with Marantec Digital models 302, 304, 306, 313, 317, 318, 321, 323, 382, 384, 392, 394 (433MHz). Compatible with Marantec Command models 131, 132, 222, 231 (433MHz). This remote works only with garage door opener receivers operating at 433.92MHz Multi-bit frequency. Compatible with Marantec Comfort models 50, 51, 60, 211, 220, 220.2, 250, 250.2, 252, 252.2, 500, 510, 520, 580, 800, 820, 830, 850, 851, 870. Warm Tips: This garage door remote is a replacement unit, not an original accessory. Please verify device compatibility using the list above before purchase. Material: Plastic. Color: As shown. Package Contents: 2 x Remote Controllers. The package includes only the items listed; other products are not included. Note: Lighting reflections and display differences may cause slight variations in color between the image and the actual item. Measurement may vary by +/- 1-3 cm.