The Black Diamond Etrier offers a classic etrier design with no frills. It gets the job done and is relatively light. It does not have sub-steps up high, which limits your options when top-stepping. This aider also comes in a 5 step size.
NOTE: All manufacturers count aider steps differently so when comparing size it is more important to count length than the number of steps. This Black Diamond 6 Step is about the same length as the Metolius 5 Step, the Fish 5 Step and the Petzl WallStep (7 Step).
While this is a solid aider, we would rather have the Metolius 5 Step Aider because it comes with reinforced steps and sub top steps and costs $8 less. Or, if we wanted the ultimate aider for The Nose or Half Dome and didn't have budget restraints, we would go with the Petzl Wall Step Etrier. Or, if we were on a budget, less than $5 more gets us two Fish Smart Aiders. Then again, if you already own a pair of Black Diamonds there is no immediate need to change because they will get the job done.