This item appears to be a special Newport product – I could not find it in the literature anywhere. It is a large plate-glass first-surface mirror used as part of a holography optical setup. The mirror is held by a black anodized aluminum frame.
The mirror dimensions are 7.5 inches tall, and 10 inches wide. The mirror does have a coating which I believe is optimized for HeNe lasers (pale salmon color when viewed at a glancing angle).
The rear of the mirror frame carries a pair of Newport 410C post clamps, 5.5 inches long. Also included are a pair of Model 45 damped rods.
All components are in flawless condition, including the mirror (in the first photo it is reflecting a piece of black velvet – mirror surface can be more easily seen in the third photo). We also have a larger mirror of similar construction available.
Photo set 622