Amazon.com : Heliopan 77mm Neutral Density 4x (0.6) Filter (707736) with specialty Schott glass in floating brass ring : Camera Lens Neutral Density Filters : Electronics
Heliopan 46mm UV ES E46 Filter Black for Leica Summilux-M 35 50 1.4 ASPH | eBay
Amazon.com : Heliopan 46mm Neutral Density 8X (0.9) Filter (704637) with Specialty Schott Glass in Floating Brass Ring : Camera Lens Neutral Density Filters : Electronics
Amazon.com : Heliopan 72mm UV SH-PMC Filter (707211) with Specialty Schott Glass in Floating Brass Ring : Camera Lens Sky And Uv Filters : Electronics