GCM-0858 Lens and Mirror Holders

GCM-0858 mounts show layered black plates, red hand-adjustment knobs and white-tipped optic-contact screws. Five dedicated images explicitly label 20, 25.4, 30, 40 and 50.8 mm clamping diameters with screw locking. The GCM-0858381M image supplies no diameter and appears to reuse a side marking from a different model, so its actual size cannot be verified from the model code. “Precision” is supplier product naming rather than a numeric accuracy rating; travel and stability data are absent. English artwork illustrates the family only.

Five labeled grip sizes

Dedicated images for GCM-085820M, 0858254M, 085830M, 085840M and 085850M label 20, 25.4, 30, 40 and 50.8 mm clamping diameters respectively. These are source grip labels, not guaranteed clear apertures or optic-thickness ranges.

One unresolved size

The GCM-0858381M image names the model but omits its grip dimension; the product side text appears to come from the 085850M photo. A possible 38.1 mm interpretation of the code is not treated as confirmed data.

Adjustment and locking

The black moving plate surrounds the optic opening. White-tipped screws contact the optic and red knobs adjust the mount. Axis count, movement per turn, backlash, force and contact-tip material are not specified.

Before ordering

No actual lens is shown as supplied. Check optic curvature, coating and thickness, plus the contact method for sensitive surfaces, and request a model-specific packing list.

Selection checklist

Choose by an explicitly labeled grip diameter

Request a dedicated dimension drawing for the 381 model

Check optic thickness, clear aperture and contact tips

Request precision, load and supply information

To be confirmed

Actual clamping diameter of GCM-0858381M

Clear aperture and optic thickness per model

Adjustment axes, travel, backlash and stability

Optic inclusion, materials and pack quantity