Applicable scenarios
Super soft:Fabric/leather/car interior/glass etc. are easily damaged
Relatively soft:Daily carpets/mats/wooden furniture/glass/kitchen and bathroom/shoes and clothing, etc.
Moderate:Outdoor tiles/wooden floors/walls/car mats
Harder:Daily tiles/floors/stones/kitchen and bathroom/metal surfaces
Super hard:Outdoor tiles/floors/fish ponds/stones/walls/ships and other items that are not easily damaged