Lee Filters Lee Neutral Density Polyester 4x4" Filter Set w/ Gelsnap Holder GSND
FOTGA Optical Glass 100mm ND1000 ND 3.0 Square 4x4" Filter 10 Stops as LEE Big Stopper|Camera Filters| - AliExpress
Tiffen ND-Filter 4x4, ND8x = ND 0,9 - needcam
Cinegear 2016: NiSi's 4x4 cine filter holder is lightweight and inexpensive - Newsshooter
UJM 52/55/58/62/67/72/77/82mm Metal Adapter Ring +100mm Square Filter Holder for Haida Lee Hitech Cokin Z PRO 4X4"/5.6/5 Filters|ring bracket|holder switchholder mobile - AliExpress
CineMorph Matte Box Anamorphic Looks Filters — Vid-Atlantic Media Productions