Usually it costs about 30USD-50USD. - 1 x Filter.
eBay
VOLODYMYR for DJI Avata 2 Filter Set MCUV ND8 ND16 ND32 ND64 ND8PL ND16PL ND32PL ND64PL Filter for DJI Avata 2 Accessories
Aliexpress UK
Functions include multi-coating to reduce flare, internal reflection prevention, and a slim design for ultra-wide-angle lenses. Experience the combined effects of 'Starry Night' and 'Pro Softon' in a single filter with the Kenko Starry Night Pro Softon.
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NEEWER ND Filter Set for DJI Osmo Action 4/Action 5 Pro Filter Kit Action Camera Accessories Multicoated HD Optical Glass
Aliexpress UK
In good used condition and full working order
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New Camera Lens Filter Metal Adapter Ring 49mm-48mm Step Down Ring Set 49 To 48 49-48mm 49-48 Filter Adapter Camera Adapter Ring
Aliexpress UK
Freewell LPR filter to fit DJI Mini 3 Pro Drone. Has had little to no use. Light Pollution Reduction filter.
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Kase Armour Magnetic 100mm Square Filter Holder System for 67/72/77/82mm Camera Lens & Lee Haida 100x100mm 100x150mm Filter
Aliexpress UK
In good used condition and full working order
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SmallRig X half Magnetic VND Filter ND2 - ND32 for FUJIFILM X half Black/Sliver Magnetic VND Filters Protect Camera Lenses 5225
Aliexpress UK
Item Type: Light Pollution Reduction Filter. The filter's outstanding clarity enhances the overall video and photo quality, making every image clear. Easy Installation: The LPR filter is designed with a knurled texture on, making it easy to install and remove.
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Sculpfun iCube Pro 5W Laser Engraver Cutter with Smoke Filter Temperature Alarm 130x130mm Comes with a smoke filter UK
Aliexpress UK
Photo filter effect type Neutral Density. Water resistance level Waterproof.
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FOTGA Optical Glass UV-IR CUT filter 52mm 58mm Infrared Pass X-Ray IR UV Filter for Canon Nikon DSLR Camera
Aliexpress UK
UHC Filter Size:Approx.28.5x0.6mm/1.12x0.02in. Type: High Contrast Filter (UHC Filter). Features: Substrates: precise polish substrates, good parallelism and surfaces precise. Thread: 28.5x0.6mm. Double-sided fine polishing and polishing process ensures high parallelism Coating: double-sided multi-layer coating, the backside increases the penetration film and reduces the reflect light.
eBay
NEEWER ND1000000 Fixed Neutral Density Filter 16.5 Stop ND Filter for Camera Lens with Multi Coated HD Optical Glass
Aliexpress UK