Hoya 55mm Half Neutral Density (ND) x 4 Glass Filter S-55NDH4X
Zomei 55mm Fader Variable Nd Filter Adjustable Nd2 To Nd400 Nd2-400 Neutral Density For Canon Nikon Hoya Sony Camera Lens 55 Mm - Camera Filters - AliExpress
Hoya 49mm Neutral Density NDX8 (HMC) Filter – Pictureline
Bower FN55 Variable 8-Stop Neutral Density Filter, 55mm - Black - Walmart.com