The Surefoot NX Series plates offer a number of benefits, including double-safety-stops, double-dovetail profile (offering ease of use for quick release flash brackets), and compatibility with all other North American 'Arca-Swiss' style lensplates. This plate is functionally identical to the NX3 (5.5" plate) but is quite long enabling terrific balance adjusment. The NX4 is 7 inches/17.78 cm long and fits most larger telephotos with multiple mounting holes such as: 400mm f/2.8 500mm f/4 600mm f/4