DMM cams have been some of the most popular in the UK recently, but with an increasingly wide choice of brands on the market choosing the right device can be confusing business.

Having used them in both their 3 and 4 CU (cam unit) configurations for several years I can confirm that their popularity isn’t just because we Brits like to support local industry! This review will focus on the aspects of the Welsh forge masters’ camming unit that make it one of the best available.

The Range
The range is split into 11 sizes, covering a total range of 13mm – 100mm. They are rated to 14kN and like all quality cams can be used as passive protection due to the engineered ‘cam stops’. The passive strength of the cams, resting on these cam stops, is 10 kN.

Design
They utilise a double-stemmed design which gives plenty of room for fingers and thumbs when placing them, especially when in a rush or while wearing gloves (or both!). One of my main requirements for cams is that they allow me to place them quickly, and being able to slip my hand into the trigger position with ease is a key reason for 4CUs finding a position on my harness. Personally I have always found single stemmed devices to be that much more ‘fiddly’ to place, although with the imminent launch of the new DMM ‘Dragon’ cam range this may change....

As well as being highly ergonomic, there are other aspects of the 4CU design that give them the edge over other cams. One of the best aspects of the range is that they are colour coded, which makes picking the right one easy and instinctive – another feature that makes rushed placements much easier. DMM also produce several of their lightweight karabiner ranges in matching colours, so if you really like the colour coding idea you can put each cam on a matching karabiner!

I have always found that it is good to have 4CUs clipped with an individual karabiner (rather than several cams on one). This is because I often clip them directly into the rope when the doubled sling is extended, which brings me on to my favourite feature...


The addition of a sling that extends means that often you need not bother with a quickdraw. This adds to the weight saving benefit of 4CU’s and will be a relief if, like me, you regularly run out of quickdraws! Using the sling fully extended affects the strength rating of the unit slightly, but being 12 kN still (rather than the 14 kN when doubled) this is nothing to worry about.
Another cool feature is the option to thread string through two holes in the trigger bar. You will probably understand how frustrating it is when your cam is buried in a crack out of reach, and having something to grab to release the trigger in these situations is a great attribute.

Compatibility with Wild Country
A while ago DMM changed their colour scheme (and also the actual cam heads themselves) to match the corresponding Wild Country sizes. This means that people who are used to Wild Country Friends can add 4CUs to their collection and use them interchangeably.
The new cam heads have holes in them, and I assume this minor alteration is due to the never ending drive to make climbing gear lighter.

Lightweight
Indeed, DMM seem to be the leaders in lightweight technology in climbing gear. Their karabiners have been getting smaller and lighter for quite a while now and they are so svelte these days that I sometimes wonder how much further they can go. The lightweight theme appears to be the company ethos, and it is serving them very well.
4CU’s have always been part of the ‘light is right’ drive and they are another excellent example of how the trend in hardware is increasingly loosing weight. According to DMM, “average 20% weight saving means that the climber can ‘sew up cracks’ with a much lighter rack. Another way of looking at it is that climbers can place 20% more cams, feel much more secure, and still come out even on the weight”.

Durability
The lightweight nature of these cams does not seem to mean a compromise in terms of durability. My oldest 4CU has seen better days but, with regular cleaning and some WD40, still does the job superbly.

Many cam wires fray and twist after many years of being stuffed in cracks. On the 4CU range, the trigger bar is allowed to slide on the cam wires, keeping the wires in better condition than if they were secured, as they are on other models.

So, to summarise, 4CUs are an excellent choice for someone looking for a versatile, lightweight and easy to use camming device. They have been my choice of cam for many years and while I have used most of the other brands on the market, I always reach for my trusty 4CUs when I rack up for a tricky route.

Purchase the DMM 4CU here.