Based on this product's specifications, here are some alternatives and similar models
Neutral Density (ND) Variable Filter K&F 77mm Fader ND8–ND2000 model SB6581
Summary description:
Variable neutral density (ND) filter K&F for 77 mm lens threads, model SB6581. Adjustable density range ND8 to ND2000 provides control over light transmission for longer exposures and wider apertures in bright conditions. Designed for landscape, long-exposure, and motion-blur photography, the filter reduces incoming light without altering color balance and mounts directly onto compatible lenses.