LBTEK Continuously Variable Neutral Density Filters are composed of UV-grade fused silica substrates and a full 270° metal (Inconel) coating, designed for a transmission wavelength range of 240-1200 nm. The central aperture diameter of the continuous neutral density filters is uniformly 7.5 mm, facilitating mechanical mounting, and the OD value can be adjusted by rotation. Although classified as reflective neutral density filters, the Inconel coating still absorbs a portion of the incident light. To ensure optimal performance, it is recommended that incident light enters from the side coated with Inconel. Additionally, caution should be taken to avoid contact with this unprotected metal coating, as touching may scratch the unprotected surface. For cleaning, the use of an air blower is recommended.

The LBTEK Neutral Density Filter Mount allows the installation of NDFR series filters with a central hole diameter of Ø7.5 mm onto the rotating shaft. To install the filter, first use the included 1.5 mm hex wrench to tighten the fixing screw on the side of the NDFR-PM to lock the rotation. Then, use the included 2 mm hex wrench to remove the silver hex socket screw. Place the filter between the two washers, then reassemble the rotating wheel and screw combination. Please note to maintain the original sequence of flat washers and wave springs when reassembling, and securely fasten the bolt. The package includes one each of 1.5 mm and 2.0 mm hex wrenches.

LBTEK Mounted Continuously Variable Neutral Density Filter features mechanical housing with angular scales and a rotation axis. The mount is precision-designed to minimize the impact on the optical element's clear aperture. The side with the scale is the coated surface, and for optimal performance, it is recommended to have light incident from this side.