1. Optical glass, precision grinding and polishing, high-definition imaging, 2. double-sided multi-layer nano-coating process, restore the true colour, Double-sided waterproof, oil-proof, for your lens protection 3. aviation aluminium frame material, logo engraved by laser engraving will not fade, dark grey frame to prevent light leakage and ghosting, 4. is adjustable, you can adjust the light by rotating the gear and choose the right luminosity for , 5. Installation will not damage the lens, change the filter at any time, do not let you miss the wonderful moment, Knurled pattern is set on both sides of the frame, easy to install and remove. Cautions. 1. Only UV filters can transmit 98.5 per cent of light; /ND- filters cannot be expressed in terms of light transmission, 2. only filters can be adjusted, other filters cannot be adjusted, 3. the filters are only compatible with GO2, GO3, 4. filters are not waterproof, ND/UV waterproof, please note before purchase. Filter Type: Material: Aluminum optical glass colour: Dark gray Package Contents: 1 x Filter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.