4VFH Variable Filter Holder provides a possibility flipping filters in and out of the optical path. Filter replacement is fast and easy. Two models are available - for 25.4 (1") mm and for 50.8 mm (2") optical filters. Maximim filter thickness for 2" models is 4 mm, and 4.5 mm for 2" model. Standard models have five slots for filter mounting. All contact surfaces are covered with plastic to prevent scratches. Holders with different mounting slot quantity are available on request. M10x1 mouting hole is made in the base of the holder for fastening on optical tables or post holders. 4VFH is made of black anodized aluminium (body and mounting slots). The standard models come without filters.