Most climbers (myself included) tend to view climbing slippers as a good option for training or when climbing routes where precise footwork is less of a concern. This makes sense when you consider that slippers tend to lack laces (hey, that’s why they’re called slippers) and feature softer midsoles. What you tend lose in precision and control, you gain in convenience (easier to put on and take off when training). Plus, thanks to the softer midsole, you also gain the ability to pull with your feet on highly featured steep terrain. In terms of the closure, the Mutant hits the traditional slipper mark by eschewing laces and using a wide elastic panel backed up with a single hook-and-loop strap. This setup is popular with many manufacturers because it works; you get convenience, while maintaining the locked-in fit needed for heel hooking.

Where the Mutant starts to diverge from traditional slipper designs is in the forefoot upper and the midsole. On the upper, Boreal has added a Friction Skin coating (finely ground Zenith Pro shoe rubber that’s mixed with glue and then painted on). This thin rubber layer not only improves toe-hooking but also provides a few less-obvious benefits. Unlike the thicker rubber toe patches found on many shoes, the Mutant’s rubber layer conforms more easily to the shape of the climber’s foot. This increases comfort and improves the shoe’s fit. This rubber skin also helps control stretch for more consistent performance during the life of the shoe.

Now let's look at the midsole. As I stated earlier, most slippers tend to feature a relatively soft midsole. The Mutant, however, ignores this established pattern and instead uses a moderately stiff midsole. Initially, I was not sure what to make of this added stiffness in what obviously looked like a conventional slipper. But after using the Mutant (for more than three months), I began to understand the benefits of this design. The midsole is not so stiff that it inhibits performance on steeper boulder problems or routes. In fact, it flexes enough that you can still pull with your feet on highly featured foot holds. But it’s during less cave-like climbing where the benefits of this stiffer midsole really begin to shine. I’m talking about routes and problems with smaller footholds where you really need to focus on using your feet. In these situations the Mutants are definitely better than most conventional (soft) slippers. Now don’t get me wrong. The Mutants are not stiff planks. They just happen to have the right combination of support and sensitivity needed during challenging real-world climbing situations – again, think small footholds rather than giant blobs of red-coloured resin jutting out from a plywood wall. This precision is further enhanced with Boreal’s unique Lateral Torsion System, which consists of a tensioned band that runs from the instep to the heel. This band adds power and control when standing on small holds and also improves security during difficult heel hooks.

From a fit perspective, the Mutant offers an asymmetric downturned last with a secure medium-volume heel and forefoot. The forefoot is constructed to accommodate a curled toe profile. While this is nothing new for many experienced climbers, some beginners – weaned on shoes that encourage a flatter toe profile – might want to reconsider how they fit the Mutant. Finally, I can’t say enough positive things about Boreal’s new Zenith Pro rubber. It’s sticky, has good edging qualities and is surprisingly durable.

The Mutant is another great new shoe from Boreal and is ideal for any climber looking for a versatile performance-oriented slipper. I like it a lot and it’s currently in my regular shoe rotation.

You can find out more about the new Mutant and other Broreal products at http://www.borealoutdoor.com/