WonderPana 145 Essentials CPL Kit - Core Filter Holder with Slim Circular Polarizing Filter for Canon 17mm TS-E Super Wide Tilt/Shift f/4L Lens Premium Grade Anodized Aluminum WonderPana 145 Core Unit for the Canon 17mm TS-E Super Wide Tilt/Shift f/4L Lens Silm double threaded Circular Polarizer (CPL); made of high quality optical glass Perfect for landscape photography and video; CPL enhances color saturation and contrast 145mm x 1mm standard filter thread enables filter stacking (other Fotodiox 145mm filters; UV,MC-CPL,ND4/8/16/32/1000); heavy duty inner-pinch cap included 24 Month Manufacturer Warranty