Weighing in at 244g, these single-sided SPDs are a pretty light pedal for less than 40 quid. If you're really saving the grams you can swap the nicely machined chromoly spindle for a more exotic titanium one (200g per pair), but you'll pay £89.99 for the privilege.
The cleat mechanism is SPD compatible and 4-degree float cleats are supplied. Be careful with the tension adjuster though; if you loosen it too much then the whole thing comes apart – not something you want to be fixing in a rainy lay-by.
Other than that, the build quality is pretty good; the sealed bearing/bushing spindle assembly is smooth running and easy to strip and clean. The paint finish scuffs fairly easy, and there was some rust on the cleat mechanism after rainy rides, but the issues were only cosmetic. Cleat entry wasn't as smooth as other SPDs we've tried – a good dose of GT85 helped but we still found it a bit hit and miss. If you're looking for lightweight, single-sided SPDs then you could certainly do worse, but if you struggle to get clipped in you might not get on with the Mutants.