Revar Cine Rota-Tray 4×5.65/138mm Variable ND Kit - a matte box based solution to neutral density - Newsshooter
Tiltaing Mini Matte Box | Tilta
Amazon.com : Tilta Mirage VND Kit – Modular Matte Box with Variable ND Filter + Accessories : Electronics
A Camera Matte Box that works with SCREW-ON FILTERS // SmallRig Mini Mattebox - YouTube
PolarPro BaseCamp Matte Box Updates and New Filters | CineD
Amazon.com : Runshuangyu 3Pcs Set 4x4 Full Neutral Density ND2 +ND4+ ND8 Filter ND2 4 8 ND Filter with Bag for Swing Away Matte Box Holder : Electronics