Features: Specially for 12 Black / 11 Black / 10 Black / 9 Black cameras. The function of the ND filter is mainly to reduce the amount of light entering the camera and bring more exposure option. Installation and disassembly, quick and convenient. The filter also protect the camera lens, certain dust-proof effect. All 52mm camera lens filters, can be installed on the action camera adapter. Specifications: Material: PC Size: Approx. 5.4cm/2.1inches Interfaces size: 52mm ND frame material: aluminum ND lens material: optical glass, polarizing film Adjustable of ND lens: ND2-ND400 Package Includes: 1Pc Adapter 2Pcs Filter 1Pc Lens Cover 1Pc Hex Wrench note: When the adjustable ND filter is at the junction of the two limit values, shadow may appear when use. Please allow 1-2cm errors due to manual measurement. Please allow for slight color differences due to different display resolution.