Amazon.com : 58mm Variable Neutral Density NDX Filter for Panasonic Lumix DMC-GH4, GH4K : Electronics
52mm ND2 400 Neutral Density Fader Variable ND filter for Panasonic Lumix G Vario 45 200mm F4 5.6 II Power OIS GH5 GH4 GH3 G7 G6|Camera Filters| - AliExpress
Panasonic DMW-LNDH55 55mm 0.9 Neutral Density Filter DMW-LNDH55