DUO Kit inc. 2x NX-Series Filter frame for 100x150mm filters with 2mm tickness from other filter manufacturers Compact and Solid aluminium 100mm Filter-Holder using filter-frames Compatible with COKIN CREATIVE adapter rings from ø49mm to ø95mm Compatible with many 100mm filters with 2mm thickness from other manufacturers and with COKIN NUANCES Extreme, IR720 and CLEARSKY NX-Series has an independant C-PL filter rotated by a dedicated wheel and is designed for long-exposure photography with integrated foams to prevent light leaks.