42mm Binocular/Monocular Objective Lens Caps Internal Diameter 51.8-53.3mm Rubber Cover Set Black (51.8-53.3LC)

Quick take

This rubber objective lens cap set is made to fit binocular and monocular objective barrels in the 51.8 to 53.3mm range, including armored housings. It is best for buyers who want tethered caps that stay with the binocular during use, but the main caveat is that sizing is critical, measure your barrel before ordering.

Pros and cons

Pros

  • Snug fit for the intended 51.8 to 53.3mm barrel size (including armor), helping reduce loose caps.
  • Tethered rubber caps hang down when in use, reducing the chance of losing them.
  • Designed to protect objective lenses from rain, dust, and scratches during everyday use and storage.

Cons

  • Compatibility depends on accurate measuring of your barrel diameter, not just your binocular’s model number.
  • Rubber flex is helpful for fitting, but buyers who prefer a stiffer cap may find the material slightly flexible.

What buyers think

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Buyer feedback focuses heavily on fit quality and usability. The most consistent theme is that these caps are noticeably better when the 51.8-53.3mm internal range matches the buyer’s objective barrel diameter, particularly on binoculars with thicker rubber armor, where smaller sizes can feel too tight. Reviewers also mention that the tethered design helps keep caps attached to the binocular, and that caps can stay out of the way once mounted. Evidence is also limited but generally supportive regarding edge finishing and an easy on, easy off feel.

Who these objective lens caps are for

These caps are a practical choice if you have a binocular or monocular where the objective barrels measure about 51.8-53.3mm on the outside (including any armor or textured rubber). They are commonly considered for popular 42mm binocular formats such as 8x42, 10x42, and 12x42, plus other optics with objective barrels in the stated diameter range.

Who should avoid them

Avoid them if you cannot confidently measure your objective barrel diameter, or if your barrel falls outside the 51.8-53.3mm range. If your binocular uses a different objective barrel size, a close match in model type can still be disappointing, and tighter sizes may require extra force to seat properly.

Fit and sizing, the part that matters most

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These are sized by the objective barrel diameter. The key buying step is to measure the outside diameter including the armoring and confirm it lands in the 51.8-53.3mm window. If your measurement is closer to a neighboring size option, it can change how snug the caps feel and how easily they seat.

Protection and daily use

The main goal is lens protection. With a rubber cover and a form-fitting design, the caps aim to reduce exposure to rain, dust, and scratches during transport, storage, and quick handling. The tethered construction is especially relevant for field use, because caps can remain attached and hang down when you are viewing, rather than being set aside and potentially misplaced.

Material and feel

Expect a lightweight rubber cap designed to stretch for a tight fit. Buyers commonly describe the balance as workable for seating the caps without feeling overly flimsy, but if you prefer a rigid “snap-on” style, you may want to compare against other cap materials and designs before committing.

Price and availability

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This is typically positioned as an affordable accessory replacement for objective lens caps. Availability can vary, so if you are comparing similar sets, focus on the size range first, then the cap style (tethered vs. loose, rubber vs. harder plastic) that best matches how you carry your optics.

Simple alternatives to consider

  • Different size objective cap set: If your objective barrel measurement lands outside 51.8-53.3mm, choosing the correct size range is usually more important than matching your binocular model name.
  • Tethered vs. non-tethered caps: If you regularly remove caps during use, tethered caps are often more convenient than caps that must be removed and stored separately.

Final verdict

If you have a binocular or monocular with objective barrels measuring 51.8-53.3mm including armoring, these tethered rubber objective lens caps are a straightforward upgrade or replacement. The strongest reason to buy is the snug, secure fit paired with caps that stay attached during use. The main reason to pause is sizing, so measure first to avoid caps that are too tight or not secure enough.

FAQ

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How do I know if these objective lens caps will fit my binocular or monocular?

Measure the outside diameter of your objective barrel, including any rubber armor or textured housing. These are intended for barrels in the 51.8 to 53.3mm range. If your measurement is outside that window, you will likely need a different size set.

Do the caps stay attached when I’m using the binocular?

Yes, they are tethered, so they remain connected to the binocular while you view. When off the lenses, they hang down out of the way for use.

What do these caps protect against?

They are designed to help protect objective lenses from rain, dust, and scratches during weather exposure, and also during transit and storage.

Will these fit 8x42, 10x42, or 12x42 models?

They are made to fit many common 42mm binocular formats, but fit still depends on your objective barrel diameter. If your objective barrels measure 51.8-53.3mm including armor, they should be a match.

Are these caps hard or flexible?

They are flexible rubber designed to stretch for a tight fit. If you prefer very stiff caps, you may find the rubber has some give, though it is intended to be snug rather than loose.

What’s the easiest way to choose the correct size if I’m unsure?

Use calipers or a measuring method you trust, measure your objective barrel diameter with the armor included, then compare your measurement to the cap’s stated internal diameter range. When in doubt, confirming the measurement is usually the safest approach.

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Specifications

Product Title42mm Binocular/Monocular Objective Lens Caps Internal Diameter 51.8-53.3mm Rubber Cover Set Black, (51.8-53.3LC)
CategoryElectronics > Camera & Photo > Accessories > Binocular Accessories
BrandGeneric
ManufacturerStealth Birding Limited
Model Number51.8-53.3LC
ColorBlack
Item Weight0.02 Kilograms
FeaturesLightweight
Objective Lens Diameter42 Millimeters
Magnification Maximum12 x
Eye Relief18 Millimeters
Exit-Pupil Diameter21 Millimeters
CoatingScratch-Resistant
Water Resistance LevelWater Resistant
Focus TypeFixed Focus
Enclosure MaterialRubber
Age Range DescriptionAdult
Manufacturer Part NumberLCV
Size MapCompact
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
  • 60.9-63.2mm
  • 45.3-46.5mm
  • 51.8-53.3mm
  • 40.8-43mm
  • 50.5-51.8mm

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