Miranda's 135mm variant — the Auto ED version without DX coupling specification.
The Miranda 135mm f/2.8 Auto ED with null mount designation is either the same lens as the Miranda-mount version in a different coupling configuration, or a version adapted to a generic mount (T-mount or other universal thread). The null mount indicates the specific coupling type is unconfirmed.
The lens delivers 135mm at f/2.8 maximum aperture with automatic aperture coupling (type dependent on mount), ED glass elements, and full-frame 35mm coverage.
If this is the T-mount or other universal screw-mount version of the Miranda 135mm, its adaptability is broader than the proprietary Miranda bayonet version. The ED glass specification makes it optically interesting for adapted telephoto use.
Identify the mount type from physical inspection. Test automatic aperture coupling mechanism. Inspect ED element condition. Verify appropriate adapter availability for modern use.