25mm Binocular/Monocular Objective Lens Caps Internal Diameter 36.6-38.1mm Rubber Cover Set Black, 37-38.2mm

Quick take

These tethered rubber objective lens caps are made to protect binocular or monocular objective glass from dust, rain, and scratches during storage and transport. They are intended for 25mm optics when your barrel (including rubber armor) measures about 37-38.2mm. The biggest buying caveat is sizing accuracy, so measure carefully before you order.

Pros and cons

Pros

  • Snug, secure fit when the barrel diameter matches the 37-38.2mm range.
  • Tethered design helps keep caps attached, so they hang down when in use.
  • Rubber construction aims to shield lenses from dust, rain, and minor impacts from scratches.
  • Smooth, well-finished cap edges are reported by buyers.

Cons

  • Fit depends on your exact barrel diameter, including any waterproof coating or armor thickness.
  • Not a one-size-fits-all replacement if your binocular/monocular objective barrel falls outside the specified range.

What buyers think

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Buyer-review evidence points strongly to fit quality as the main theme. When the barrel diameter matches the intended size window, buyers report a snug, “right” feel (not overly loose, not overly tight) and caps that stay on during use. Multiple reviews also mention the tether working as intended, keeping caps with the binoculars instead of losing them. A smaller number of comments describe the rubber’s balance of flexibility and stiffness, plus smooth edges that make the caps easier to remove and replace.

Because the product’s primary function is protection through correct sizing, review sentiment is most reliable around compatibility and how the caps behave once installed. Overall, the pattern suggests these are best when you do the measuring step up front, especially for binoculars with thick rubber armor.

What these objective lens caps are for

Objective lens caps protect the front glass on binoculars and monoculars, covering the optics when you are moving, storing the device, or packing it away in a case. The tethered rubber design is meant to keep the covers attached to the barrel, so they stay out of the way while you’re looking and remain ready for quick shut-down when you’re done.

Fit and compatibility: the sizing step that matters most

These caps are positioned for 25mm-class optics, but the sizing is driven by your binocular or monocular’s outside barrel diameter (including armor). The fit target is 37-38.2mm on the outside, with an internal diameter range of 36.6-38.1mm.

  • Measure the outside barrel (not just the objective lens size). If you have a thick rubber waterproof coating or armor, that thickness can change the effective diameter.
  • Match the diameter range. If your barrel measures outside the window, you’ll likely need a different size set.
  • Watch for snugness. Buyers report that the correct size feels secure without needing extra force, while undersized caps can become too tight.

Protection and everyday usability

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These covers are designed to guard objective lenses from rain, dust, and scratches. The tethered approach is a practical usability feature for birding, hiking, and general outdoor use because it reduces the chance of misplacing caps between sessions.

Several buyers also describe the caps as easy to remove and replace, and that they hang down when not covering the objective lens, which can be convenient if you prefer to leave the caps attached during active use.

Pros and cons

When they’re a good match

  • You own a 25mm binocular or monocular (including common 8x25 and 10x25 configurations) and you can confirm the barrel diameter is in the 37-38.2mm range.
  • You want front-lens protection for outdoor conditions and travel, without dealing with loose, detachable caps.
  • You prefer a flexible rubber cover that still feels stable once installed.

When you should look elsewhere

  • Your binocular or monocular’s objective barrel diameter is outside the 37-38.2mm target, especially if your device has unusually thick armor or coating that changes the measurement.
  • You’re expecting caps that fit automatically based only on “25mm” marking. These are diameter-dependent, so confirm fit measurements first.

How to choose the right set (quick checklist)

  1. Grab a caliper or ruler and measure the barrel outside diameter, including rubber armor.
  2. Compare your measurement to the 37-38.2mm fit target.
  3. Consider your objective-to-barrel shape. If the barrel tapers or steps, measure the section where the cap will actually sit.
  4. Confirm you want objective caps. These are for the objective side, not the eyepiece.

Price and availability

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The current price can vary by retailer listing and region. To see the latest cost and options, check the product page below.

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FAQs

Are these objective lens caps only for 25mm binoculars?

They are designed for 25mm binoculars/monoculars, but sizing is based on your device’s barrel outside diameter (including armor). As long as your barrel measures within the specified range, they may fit certain compatible models beyond only one exact pairing.

How do I know which size to buy?

Measure the outside diameter of the binocular or monocular barrel, including any rubber armor or waterproof coating. This set targets a 37-38.2mm outside barrel diameter (internal diameter 36.6-38.1mm). If your measurement is outside that range, you should choose a different size set.

Do the caps come off during use?

The tethered design is intended to keep the caps attached to the barrel and hanging down when in use. Buyers commonly describe the tether as effective for preventing lost caps.

What protection do these provide?

They are meant to protect objective lenses from dust, rain, and scratches, including during storage and transport.

Will these work on armored binoculars?

They can, as long as your barrel diameter including the armor falls within the 37-38.2mm range. This is why measuring the outside diameter is the most important step.

Specifications

Product Title25mm Binocular/Monocular Objective Lens Caps Internal Diameter 36.6-38.1mm Rubber Cover Set Black, 37-38.2mm
CategoryElectronics > Camera & Photo > Accessories > Binocular Accessories
BrandGeneric
ManufacturerStealth Birding Limited
Model Number36.6-38.1LC
ColorBlack
Item Weight15 Grams
FeaturesLightweight
Objective Lens Diameter25 Millimeters
Magnification Maximum10 x
Exit-Pupil Diameter2.5 Millimeters
Water Resistance LevelWater Resistant
Enclosure MaterialRubber
Size MapCompact
Age Range DescriptionAdult
Manufacturer Part NumberLCV
Age Range (Description)Adult
Special FeatureLightweight

Available variants

Size

  • 48.5-50mm
  • 53.8-55.8mm
  • 57.5-59.4mm
  • 42.6-43.6mm
  • 47.5-49mm
  • 69.7-74mm
  • 61.5-64mm
  • 32-34mm
  • 59.4-60.9mm
  • 44.3-45.3mm
  • 37-38.2mm
  • 64.4-67mm
  • 54.5-57.5mm
  • 46.5-48mm
  • 66.5-69.7mm
  • 43.1-44.8mm
  • 45.3-46.5mm
  • 60.9-63.2mm
  • 51.8-53.3mm
  • 40.8-43mm
  • 50.5-51.8mm

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