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.