The Hardrrr scale rates each piece of equipment on three factors; Difficulty of Use, Impact & Intensity, Threshold Level.
Difficulty of Use means, how difficult the equipment is to use, including things like how much skill is required, how much preparation is needed or how much finesse, touch or feel is needed.
Impact & Intensity means, how much of an impact the equipment makes, how intense the experience is and/or how intense the feeling is that the equipment produces.
Threshold Level means, the threshold level the equipment operates at, or, how high you or your subs threshold needs to be to use the equipment.
The scale is a 1 to 5 Whip scale, with 1 being the lowest rating and 5 being the highest rating.