In 1972 Chouinard Equipment released seven sizes of Stoppers. A lot has changed since then but the folks at Black Diamond (which came out of Chouinard) have been making climbing nuts longer than anyone in North America. Black Diamond's Stoppers are some of the most durable nuts around. They will easily last even the most avid climber for many seasons. BD is tied for second for the largest range of sizes in a standard set (although they claim #1 and #2 are for direct aid only). The Stoppers set had one of the most usable size ranges we tested with little or no gap between sizes. Color-coded heads help to distinguish between sizes. The variety of placements was average but they worked well in a great variety of rock types.
They are simple nuts that are easy to assess in the rock (a good trait for climbers just breaking into the sport). They fit most constrictions and parallel sided cracks quite well. One downside is their inability to fit flaring cracks well like the top scoring DMM Offset Nut. They are stout, dependable nuts that excel in the smaller sizes and are average in the larger. We lean toward getting the Cypher Huevo because it is very similar but less expensive.