Vizen Marketing - πMade for SONY camera bodies used clip filter, and the color shift issue that may occur due to the wide angle SLR lens in peripheral areas of the image
STC In-Body Clip Filter - Inserting Filters Right Between Lens and Sensor | CineD
An overview and review of STC's filter Series - YouTube
STC Optics announced the rumored 6-stop ND clip filter - Photo Rumors