Omega #421-902 lens plate with 1/2" cup and 42mm hole for mounting certain enlarging lenses with 42mm mounting thread on the #421-900 Single Lens Mount for D5500 and ProLab II enlargers. For specific applications for this lens plate, please refer to our D5500 / ProLab II Lens Mount Reference Chart.
Note: These lensboards are not threaded - a 42mm retaining ring is required to mount the lens.