It features two filter slots, a configuration that accommodates two rectangular filters. Each slot is designed to grip an installed filter only along the surface of the filter's edges. Contact with a filter's front or rear-facing surfaces is avoided, particularly when using graduated filters whose effect can be adjusted to better suit changing lighting conditions or creative demands by sliding them up or down within a filter slot. The S6 features a new locking system to lock the main filter holder in position (when used with an S6 Adaptor). The integrated wheel can be easily rotated to lock the holder in place with a locking system that feels natural and easy to use. After being fitted onto the adapter ring, the filter holder's pull-and-release locking pin helps to provide a reliable, yet adjustable connection while the entire filter holder kit can be rotated 360°, permitting the use of graduated neutral density and other filters that are enhanced by varied positioning. The S6 holder is compatible with 2 x 150x150mm or 150x170mm filters and requires an S6 adaptor (available separately) to mount to a lens.