BoliOptics Microscope Eyepiece Reticle 20mm - Precise Crosshair Scale

In this review of the BoliOptics Microscope Eyepiece Reticle the bottom line is simple: this is a purpose-built crosshair micrometer for users who need a precise, compact scale inside an eyepiece. The reticle installs into a 20mm diameter eyepiece and provides a 10mm/100 division X-axis crosshair that is useful for quick measurements and alignment. Our review finds it best for lab technicians, hobby microscopists, and optics users who already know their eyepiece inner diameter and need a positive-background, high-contrast scale rather than a full grid.

Key Features

• Optical grade glass: The reticle is made from high quality, optical grade glass for clear, distortion-free markings when viewed through a microscope.
• 20mm diameter fit: The 20mm outer diameter is compact and fits eyepieces with that inner mounting size when measured carefully.
• 10mm/100 Divisions: The 10mm span divided into 100 increments provides fine, repeatable readings for small measurements and alignment tasks.
• X-axis crosshair scale: The single-axis crosshair reduces visual clutter while giving a precise reference line for measurements and centering.
• Positive background: The positive background type produces dark markings on a lighter field for high contrast against many specimen types.

Who It's For

The reticle is aimed at microscope users who already work with eyepiece-mounted scales: technicians, students in optics courses, amateur microscopists measuring small features, and professionals who need a simple linear reference inside their eyepiece. It is particularly useful when a single X-axis measurement or centering aid is preferred over a full reticle grid.

Users should measure their eyepiece inner diameter before purchase and avoid this if their eyepiece does not accept a 20mm reticle. Those who need multi-axis grids, variable scales, or built-in illumination in the reticle should look for alternative products designed for those needs.

Pros & Cons

Pros

• Compact 20mm size fits eyepieces that accept this diameter and installs without altering optical path.
• High quality optical glass keeps markings sharp and minimizes distortion across the visible field.
• Fine 10mm/100 div graduation enables precise incremental measurement and repeatability.
• Positive background and clear crosshair improve visibility for many specimen types.

Cons

• Limited to a single X-axis crosshair scale, so it is not ideal for users who need full grid reticles or multi-axis measurement.
• Requires exact measurement of the eyepiece inner diameter to ensure a proper fit.

Specifications

Product	BoliOptics Microscope Eyepiece Reticle
Reticle Type	X-Axis Crosshair Scale
Diameter	20mm
Scale	10mm / 100 divisions
Reticle Dimensions	20 x 1.5mm
Background Type	Positive
Material	Optical grade glass

Our Verdict

The BoliOptics 20mm crosshair reticle is a focused, cost-effective tool for anyone who needs a precise single-axis scale inside an eyepiece. It is good value when the user measures their eyepiece diameter in advance and wants a high-contrast 10mm/100 div linear reference without extra visual clutter. Buy if you need a compact, reliable micrometer reticle; look elsewhere for multi-axis or larger-format reticles.

Frequently Asked Questions

Will this reticle fit my eyepiece?
Measure the inner diameter of the eyepiece at the mounting area; this reticle is sized for a 20mm fit and must match that inner diameter.

Is the scale easy to read?
Yes, the positive background and optical grade glass produce clear, high-contrast markings for the 10mm/100 division scale.

Can this replace a full grid reticle?
No, this is a single X-axis crosshair scale intended for linear measurements and alignment; choose a full grid reticle if you need both axes.