Camera Accessories
Fotodiox Pro 145mm Neutral Density 8 (3-Stop) Filter - Pro1 Multi-Coated ND8 Filter (works with WonderPana 145 & 66 Systems)
Premium Grade Optical Glass Filter 145mm x 1mm Standard Thread, both in the front and rear Premium Grade Anodized Aluminum Filter Ring Other Available 145mm Filters include CPL, ND4, ND8, ND16 & ND32 Filters 24-Month Manufacturer Warranty
https://www.bizrate.co.uk/cameraaccessories/fotodiox-pro-145mm-neutral-density-oid38944341420.html