Pack of three foam gaskets for 85 x 85 or 100x100mm Filters.
Unlike the Firecrest 100mm filter holder, many older design systems such as the Formatt-Hitech 100mm filter holder doesn't offer any specific protection against light leak. A foam gasket can be used to help block this light entering behind the filter and ruining your landscape or long exposure shot. The gasket will make a big difference however it should be noted that it is not a definitive solution.
Gaskets are not required if you are using the new Firecrest 100mm Filter holder.