Belay glasses are a non-adjustable piece of gear that only come in one size per model. This is why it’s helpful to know what to look for in the fit before you buy.

Unlike most other types of rock climbing gear there are only a handful of climbing brands making belay glasses. This is both a pro and con. A pro because there’s not an overwhelming amount of options to choose from and a con because there’s not a lot of different technologies or sizing differences. That said there are some subtle and notable differences that we’ll go into now.

Prism Size

The prism is the main piece that makes the belay glasses work. The prism is what changes the angle of vision that your eyes are seeing. Some prisms are slightly bigger than other prisms, which make it a bit easier to see the climber. Sadly, most companies don’t mention the size of their prisms. Here are some examples of the quarter to half inch differences:

And some additional measurements from a comparison by PitchSix, who has compared a few more models (converted from mm, to be consistent with the above):

  • Belay Specs – .98″ x 1.06″
  • Belaggles (no longer made, but you could find used) – 1.57″ x 0.7″
  • Y&Y Classic (metal frames) – 0.86″ x 0.51″

Usually the prism size accounts for the main difference in price, as this is the most expensive part of the glasses. So, if you find a particularly cheap pair of belay glasses, likely, it has a smaller prism.

No matter the price, we have seen reviews from every brand of belay glasses where the prism quality isn’t as expected. Either double images, a particularly warped image, blurryness, etc is possible. This is one of reasons we recommend trying on in store or buying from a shop with a helpful return policy. In person, you quickly be able to tell the quality of the prism by testing it just looking at walls and ceilings. If you see double vision, or a significantly warped image, try another pair.

Prism Deformation 1
These glasses have a prism deformation. Fortunately (and surprisingly), this inconsistency does not cause any problems while wearing the glasses.

Prism Angle

The main goal of belay glasses is to reduce neck strain while belaying a climber on a vertical or slightly overhanging cliff. Most glasses come with one standard angle which is about 60º. This means that on vertical or overhanging you’ll still bend your neck (a little) to get a good view of your climber. The bend in your neck is minor compared to belaying without belay glasses.

Setting them apart, the PitchSix EyeSend glasses have a lever where you can adjust the angle anywhere from 60º – 120º. Though, the most useable range to keep looking straight ahead, is more like 70º – 110º — unless you want to check out the brim of your helmet or your partner is climbing a particularly flat slab pitch. With the wide angle prism adjustment, you can essentially always look straight ahead to watch your climber, whereas most belay glasses you still have to look up a bit. We have more photos of this angle difference and the EyeSend glasses in general in our full review.

PitchSix Belay Glasses prism angle up down 2
Left the lever is down at 60º and right the lever is up at 120º. The PitchSix glasses are the only belay glasses with an adjustable prism.

Fitting over Glasses

If the belay glasses fit over your glasses really has to do with the arm length of the glasses. It seems most belay glasses weren’t specifically crafted to go over glasses (sunglasses or prescription). The belay glasses we tried had to go super close to the glasses or if the length was longer they could fit lower on the nose and not squeeze the glasses. We imagine it’d be personal preference and also depend on the size of your glasses for what will feel best. Personally, we found a longer arm length to be more accommodating and comfortable as the belay glasses didn’t smush against our normal glasses. Measuring from the middle of the nose bridge to the end of the arm we found these measurements for our pairs:

Belay Glasses over sunglasses 3
From left to right: Cypher Belay Glasses, Metolius Upshot, and PitchSix EyeSend.


Despite our name, WeighMyRack, we consider this a non-issue as most folks will not take belay glasses on a multi-pitch and they’ll likely be cut from the bag before a super long approach. Most glasses made today seem to be between 40 – 60 grams (not including the case), which is about 1 solid gate carabiner – a lockers worth of weight. We’ll geek out on weight more when we add belay glasses to

Included Accessories

Some glasses come with a carrying strap/lanyard or offer an optional strap. A strap is most helpful if you’re belaying a climber multiple times in a row or belaying multiple climbers in a row. If you’re swapping whose climbing, you’re probably swapping belay glasses with them, or taking them off to climb, so it’s less important.

Most glasses come with some sort of carrying case. A hard (vs soft) carrying case is nicer for throwing the glasses in a pack with a lot of other objects.

Casses Example 4
The glasses we tested all came with a hard case that included a loop that you could hang the case from. Left to right: Cypher, PitchSix, Metolius.

Where They’re Made

Although country of origin isn’t about how the glasses fit your face, it could be how they fit your values. CU Belay Glasses are produced in Germany and assembled personally by the belay glass inventor, Albi Schneider. Belay Specs and PitchSix are the only brands we know of that are made in the USA, coincidentally, both brands glasses are made in Salt Lake City, Utah. As far as we can tell, it seems the rest of the glasses are made in China.

Where to Buy

As usual, we suggest buying gear from your local gear shop, so you can try on before buying to check the fit and prism quality in person.

And as a heads up, unfortunately, the selection of belay glasses in stores is usually limited. For example, at the time of this article, REI only has the Metolius Upshot belay glasses in stock and Backcountry only has the Cypher Belay Glasses in stock.

This is a Sponsored Post

Our How To Fit Series is generously sponsored by REI. We approached REI about this series and they were thrilled to help make it happen. All words are solely the authors and have in no way been altered because of the sponsored nature of the post. We do link directly to REI’s website for some of the products mentioned.

In regards to fit, it’s worth noting REI’s free shipping for Co-op members as well as the 1-year return policy. Members can also buy and trade in used gear.

Other articles in this series include:

Alison Dennis

Alison Dennis

Alison (she/her) runs WeighMyRack from her 17' travel trailer. She is currently touring the US and would love if you contacted her to meet up to talk about climbing, climbing gear, or if you have any fun and/or ridiculous adventure in mind.

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