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
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
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)
- Grab a caliper or ruler and measure the barrel outside diameter, including rubber armor.
- Compare your measurement to the 37-38.2mm fit target.
- Consider your objective-to-barrel shape. If the barrel tapers or steps, measure the section where the cap will actually sit.
- Confirm you want objective caps. These are for the objective side, not the eyepiece.
Price and availability
The current price can vary by retailer listing and region. To see the latest cost and options, check the product page below.
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 Title | 25mm Binocular/Monocular Objective Lens Caps Internal Diameter 36.6-38.1mm Rubber Cover Set Black, 37-38.2mm |
|---|---|
| Category | Electronics > Camera & Photo > Accessories > Binocular Accessories |
| Brand | Generic |
| Manufacturer | Stealth Birding Limited |
| Model Number | 36.6-38.1LC |
| Color | Black |
| Item Weight | 15 Grams |
| Features | Lightweight |
| Objective Lens Diameter | 25 Millimeters |
| Magnification Maximum | 10 x |
| Exit-Pupil Diameter | 2.5 Millimeters |
| Water Resistance Level | Water Resistant |
| Enclosure Material | Rubber |
| Size Map | Compact |
| Age Range Description | Adult |
| Manufacturer Part Number | LCV |
| Age Range (Description) | Adult |
| Special Feature | Lightweight |
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
Recommended next
Vortex Optics Uni-Daptor Binocular Tripod Adapter
The Vortex Uni-Daptor is a quick-release binocular adapter designed for steady tripod viewing, with a convenient way to switch back to free-hand glassing without fully removing the adapter from your binoculars. It’s lightweight and built for frequent outdoor use, though it can be pricey for a small accessory and compatibility can depend on your existing mounting quick-detach setup.
Binocular Harness Chest Pack with Rangefinder Pouch, Bino Harness with Rain Cover for Hunting
A mid-sized binocular chest pack from Wild Cedar designed for quiet, hands-free carry. It combines a no-zip binocular pouch with an adjustable harness, a dedicated rangefinder/gear pouch with magnetic flap, side MOLLE attachment straps, and a dedicated rain cover pocket.
Swarovski NL Pure FRP Forehead Rest 49161
The Swarovski NL Pure FRP Forehead Rest 49161 is a binocular accessory designed specifically for NL Pure models. It improves comfort for long viewing sessions and helps stabilize your hold, which many buyers say makes it easier to see small details (especially with higher magnification). The main tradeoffs are that it can affect how well the binocular fits in its factory case and, for some buyers, build quality issues have been reported.
MOXULE Binocular Harness Chest Pack (Bino Case with Rangefinder Pouch)
The MOXULE Binocular Harness Chest Pack is a padded, camo chest carry designed for hunters, birdwatchers, and hikers who want quick access to binoculars plus a detachable rangefinder pouch. It uses magnetic closure for fast one-handed access and adds MOLLE-style webbing for extra organization, but the rangefinder pouch attachment may be too loose for some setups.