Model differences

Open-top crystal rake or clumping-litter sifter?

An open entrance can describe two very different cleaning systems. The PETKIT Purobot Crystal Duo rakes a manufacturer-specific crystal tray; the Neakasa M1 Plus and PETKIT’s enclosed Purobot machines sift clumping litter in a rotating chamber. A cat that likes an open view does not make those supplies or maintenance routines interchangeable.

Crystal Duo: simple access, proprietary tray

The open T7/T7-G Crystal Duo is an uncovered, low-entry tray with a powered rake and two side waste traps; the separately reviewed T7-W1 adds a front-entry hood over that same P9905 base operation. Its matching PETKIT crystal litter and disposable tray are required; the manual rules out other litter brands, clay, and tofu. The trade is a familiar tray shape and no rotating globe, in exchange for a recurring all-in-one tray replacement and a narrow litter choice. The manufacturer advertises both a 30-day single-cat interval and a 45-day “optimal performance” statement in different parts of its product page, so the interval should not be treated as a guaranteed service schedule. The manual also requires a cat aged at least six months and over 3.3 pounds; it does not give a rated multi-cat capacity or maximum weight.

Its camera and connected app can show live/event information, with privacy scheduling and a manual camera-off option. Full video playback is tied to PETKIT Care+ in the manual, and the optional crystal urine-monitor supplies are separate. Alerts can prompt observation but do not diagnose illness. Read the full Crystal Duo assessment before buying into its consumables.

OpenSky and M1 Plus: clumping litter, different movement

The PetSafe ScoopFree OpenSky uses a clumping-litter sifting mechanism with an open-top rotating chamber. It stores sifted material in a waste drawer, so litter is familiar to households already using compatible clumping formulas. The chamber itself moves, which makes entry geometry and transition acceptance different from an exposed tray with a rake. The OpenSky review explains its exact litter and cleaning limits.

The Neakasa M1 Plus is another open-top choice, but its rotating sifter tips the litter rather than raking an open tray. Its standard operating plan accepts compatible clumping litter, with separate warnings about litter granule size and the machine’s automatic-mode limits. The drawer still needs regular attention; a large advertised storage interval is not a substitute for checking waste. See the M1 Plus review for the model’s exact dimensions, operating plan and setup tradeoffs.

Choose the routine before the feature list

• Choose Crystal Duo only when PETKIT’s exact crystal litter and tray are acceptable and you want a low, uncovered rake-style pan.
• Choose a clumping-litter sifter when keeping your normal litter is more important than avoiding a rotating chamber; check the manufacturer’s granule-size and cat-fit rules.
• T7-W1 is a separately reviewed P9905 + P99051 front-entry configuration; the clear hood opening and installed envelope remain unknown. See the hooded review and open-versus-hood guide.
• Do not select any of these boxes for a young or small cat unless the exact manufacturer instructions allow that animal to use automatic mode.

During a change, leave the old pan available and introduce the new system gradually. The safest short list is the one whose litter, entry, data/privacy setup and waste-removal routine all work in the room where it will live—not the one with the longest hands-free claim.