Brand
Meowant covers drums with unusually low entry steps, an open-top rotating model and a dual-rake open tray. The SC02 and SC09 pages state a 4-month minimum age and a 3.3 lb detection floor; the others publish less.
Ordered by price, lowest first.
Rotating drum
Best for: A senior or short-legged cat under 18 lb
Rake
Best for: Cats that will only use something that looks like a normal pan
Rotating drum
Best for: Small apartments with one or two average-size cats
Open-top
Best for: Cats that avoid enclosed boxes, in a home that wants a big drawer
Rotating drum
Best for: One large cat that needs room inside the drum