Newport kinematic mirror and lens mount Similar to KM100 Description: nice lens kinematic mount removed from High School laser lab. Measures: 2x2" (51x51mm). The lens holder is a bit smaller, around 51x49mm. It holds 31,7mm and smaller lenses (down to 28mm with actual "8-32" locking screw). Locking screw is short grub with plastic end to avoid damaging lenses. If you want to hold lenses 28mm you need a larger "8-32" imperial type screw, (for example: https://www.newport.com/p/DE-8-0.63). The big hole is Ø 31,75mm (1,25"). It has 8-32 thread mount to mount in breadboard or other components (remember "8-32" is similar to M4 but with bigger thread pitch). Screws are HQ plastic 100 TPI (smoother to run than metal, but probably less strength/durability if you turn them a lot in an everyday basis). High quality. Condition: normal usage marks. Nice working condition. Note: these items have been de-greased, cleaned, re-greased (with special oil, better than original grease) and checked for missing or damaged parts. Then tested and verified ok. Good functioning is garanteed. Issues: some marks of normal usage here and there.