LBTEK Stepped Neutral Density Filters are composed of UV-grade fused silica substrates and metal (Inconel) coatings, designed for a transmission wavelength range of 240-1200 nm. The optical density (OD) range of step-type neutral density filters is 0.04 to 1.0, 0.04 to 3.0, or 0.04 to 4.0, providing 8 or 10 steps of optical density adjustment through rotation. Their center hole diameter is 7.5 mm, facilitating easy installation of mechanical components. Although these filters are reflective neutral density filters, the Inconel coating still absorbs some incident light. For optimal performance, it is recommended that light be incident from the side of the Inconel coating. Furthermore, care should be taken to avoid contact with the unprotected metal coating, as contact may scratch the unprotected surface. Air blowing is recommended for cleaning.

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's Mounted Stepped Neutral Density Filters feature a mechanical housing with angular scales and a rotation axis. The mount is precision-designed to minimize impact on the optical element's clear aperture while maintaining a compact structure, making it an excellent alternative to filter wheels. The side with the scale markings is the coated surface, and for optimal performance, it is recommended to have light incident from this side.