As apposed to Free Climbing, Aiding Climbing describes a style where
equipment is used to move over the rock.
The rating system used for Aid Climbing describes the number of
sequential protection placements that can only hold bodyweight (but not a
fall). As can be expected, an increase in aid rating also increases the
potential for a longer fall.
Aiding requiring a hammer (to drive in
protection) is prefixed "A" ,whereas hammerless or clean aid is
prefixed with a "C".