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Black Diamond Micro Stopper Review

Showing a set of Black Diamond Micro Stoppers.
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Price:  $16 List | $6.73 at REI
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Pros:  Durable, fit parrallel cracks well
Cons:  Not as useful for pin scars or flaring placements
Manufacturer:   Black Diamond
By Ian Nicholson ⋅ Review Editor  ⋅  Dec 13, 2009
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Our Verdict

The Black Diamond Micro Stopper were the most durable micro climbing nut we tested. The heads are made of hard and wear-resistant copper-infiltrated iron instead of the normal brass or bronze. The large cables are less prone to kinking and feature an extremely aggressive curved taper to help them grab onto anything they can. This gave them the best holding power in parallel-sided cracks. They have relatively long heads, which allow them more surface area, and they come with two very useful placement orientations.

These are the most durable micro nut on the market and a great choice for free climbers who use them a lot. They are the easiest micro nut to clean, partially due to their shape and partially due to the copper-infiltrated iron heads, which are hard and less likely to deform. Aid climbers will appreciate their very small sizes and free climbers can gain confidence from the larger sizes on tenuous thin cracks. Aid climbers will still usually prefer DMM Brass Offsets. But if you free climb a lot, or just want a micro nut for every crack type, Micro Stoppers are great to have on the rack.

Our Analysis and Test Results


These are the most durable micro nuts in the review. Their heads are much more durable than the DMM Brass Offsets and about the same as the Metolius Astro Nut. Their burly cables are far tougher than those on DMM Brass Offsets and slightly tougher than those on Astro Nuts. We like the tall heads, which give more confidence, especially while free climbing above them. More surface area gives them more holding power, especially in softer stone. The aggressive curved taper also fits parallel sided cracks well as the nut gets hung up on irregularities (a good thing).

The Micro Stopper has two excellent orientations: each side of the nut is quite different than the other. This gives many placement options and in this respect they barely beat out the Astro Nut and are a lot better than the DMM Brass Offsets. Like all other mini nuts in the review, they feature color coding around the swage of the nut to help with size identification.


Many of the advantages of the Micro Stoppers have potential downsides as well. The shape, while helping them hold in parallel sided cracks, makes them difficult to place in old pin scars and flaring placements typical on many aid climbs. Though they offer an offset orientation, it isn't nearly as effective as the DMM Offsets in pin scars. Also, the longer faces of the heads, while adding more holding potential, often make them hard to fit in tiny placements where a shorter-faced nut would go. For less secure placements, they are not as soft and so don't grab the rock as well as others. This is more of a problem in featured or heavily textured rock.

Best Application

These are suitable for aid climbing but a better choice for free climbers who want to have a couple micro nuts on their rack at all times. When paired with the DMM Brass Offsets, you will have a nut for just about every crack type.


While not much cheaper than any of the micro nuts we tested, they are the most durable, which makes them a great long-term value.

Ian Nicholson