The reversing gear is an optional add-on accessory for the LanParte follow focus that corrects the reverse direction of Nikon and Pentax lenses so they rotate in "standard cinema direction". A convenient arm allows the reversing gear to be moved away or engaged as needed. Specifications Model number: FFRG-01 Package weight: 0.027kg Package size: 65x55x35mm Package Includes 1 * LanParte FFRG-01 Reversing Gear