The flap opening is the fit check, not the weight tier
Five of the eight doors here are sold in tiers named by weight. PetSafe’s Freedom Aluminum runs from Small (up to 15 lb) to Extra Large (up to 220 lb) in four steps, Ideal’s Ruff-Weather covers 2 lb to 120 lb in four bands, PlexiDor’s Door Series runs 40 lb to 220 lb, and the two collar-key doors split at 15 lb and 100 lb (PetSafe SmartDoor) and 30 lb and 100 lb (High Tech Pet). Patio Pacific is the exception: it sizes the Endura Flap by recommended pet height, with the five bands listed in the comparison table. The two microchip doors publish neither a weight nor a height ceiling, only the phrase “large cats and small dogs” (Sure Petcare) or “cats and the smallest dogs” (PetSafe).
None of those labels tells you whether a particular dog’s shoulders clear the hole. A weight is not a shape, and a height band gives you one dimension of a two-dimensional opening. The figure that settles fit is the published flap opening, width by height, checked against the widest point of your broadest pet’s chest plus a margin, and separately against the height of your tallest. In a multi-pet home the opening has to clear the broadest animal that will use it, which is not always the heaviest or the tallest.
Laid side by side, the published openings sort into three groups. The Sure Petcare door has the smallest published opening at 7.5 in wide by 6 11/16 in tall. Four doors publish openings between 8 and 10 inches wide: the Endura Flap Medium at 8 by 14, the Freedom Aluminum Medium at 8 1/4 by 12 1/4, the High Tech Pet Medium at 8 1/4 by 10, and the Ideal Ruff-Weather Extra Large at 9 3/4 by 17. Three publish openings 11 inches or wider: the PetSafe SmartDoor Large at 11 by 16, the PlexiDor Large at 11 3/4 by 16, and the High Tech Pet Large at 12 1/4 by 16. Those three are all rated to 100 lb and all 16 inches tall, and the SmartDoor and PlexiDor are within an inch of each other in width.
Weight bands have floors, and only one brand publishes them
Ideal is the only manufacturer here that states a lower bound for each size: Small is 2 to 12 lb, Medium 13 to 35 lb, Extra Large 36 to 90 lb, Super Large 91 to 120 lb. PetSafe, PlexiDor, and High Tech Pet publish ceilings only. That matters in a mixed household because the heaviest pet sets the ceiling, but the lightest pet has to live with the same flap, and a published floor is the manufacturer’s own statement of where the match stops. With a ceilings-only chart you are choosing the smallest size whose ceiling clears your biggest pet, and nothing on the page tells you whether the cat is still in range.
Chip, collar tag, or nothing
The eight doors use three identification methods, and the method decides what a mixed household can and cannot do.
Two read an implanted microchip. The PetSafe Microchip Cat Door reads 15-digit FDX-B chips, with an optional Microchip Key Fob sold separately for a pet whose chip is not compatible. If a pet’s chip is not 15-digit, the Sure Petcare door reads more formats; PetSafe’s route is the fob. Capacity favors PetSafe at up to 40 pets against Sure Petcare’s 32.
Two read a tag on the collar. The PetSafe SmartDoor Large reads a SmartKey RF tag, ships with one, stores up to five, and lets you adjust the detection range up to 3 feet. The High Tech Pet Power Pet Door uses an ultrasonic MS-5 transmitter collar, ships with one, and does not publish how many it can recognize. Every pet that uses either door has to wear a tag, including a cat sharing a dog’s door. The manufacturer pages retrieved for both doors say nothing about what happens when a tag battery runs down, and neither describes a fallback for a pet whose collar has come off. The Unlocked modes on the SmartDoor and the PetSafe Microchip Cat Door, and the Sure Petcare door’s free exit, are the published ways a pet without a recognized tag or chip passes an electronic door in this group.
Four read nothing. The Freedom Aluminum, Endura Flap, PlexiDor, and Ideal Ruff-Weather are push flaps; as Patio Pacific puts it, sizing and fit are the only control over which animals pass.
Door thickness, walls, and glass
Three manufacturers publish a thickness range, listed in the comparison table. The Endura Flap splits by flap count, with a separate thin-door model, and the Medium covered here is the double-flap version, so a thinner door needs one of the other two. Sure Petcare lists wood, PVC, and metal doors, stud and masonry walls with optional TUN101 Tunnel Extenders, and single- or double-glazed glass with a 294 to 320 mm (11 9/16 to 12 5/8 in) hole and the GMA101 mounting adaptor. The tunnel itself is 2 3/4 in deep and no single maximum thickness is published.
For the other four doors, no range is published, so fit to a specific door cannot be confirmed from the manufacturer’s page.
Power is the other installation constraint. The High Tech Pet door runs from an included 110V AC adapter, with a rechargeable battery backup sold separately, so it needs an outlet within reach of the door. The Sure Petcare door takes four C cells with a stated typical life of at least six months, the PetSafe Microchip Cat Door takes four AA cells, included, and the SmartDoor takes four D cells, not included.
Closing the door at night
Every manual flap here except the Endura publishes a way to block the opening. The Freedom Aluminum includes a slide-in panel, the Ideal Ruff-Weather has a lock-out slide, and the PlexiDor has a removable steel security plate with a key lock, the only key-locked closure in the group. Patio Pacific’s page for the Endura Flap describes a magnetic seal on three sides but no closing panel or lock.
On the electronic side, the Sure Petcare door has 4-way locking, a curfew mode that locks and unlocks on a schedule, and a double-locking mechanism. The PetSafe Microchip Cat Door has a manual 4-way lock: Locked, Unlocked, In Only, Out Only. The High Tech Pet door is described in the retailer listing as engaging an automatic steel deadbolt once its motorized panel is fully closed.
When the manual flap is the right answer
A manual flap is enough when three things are true: no pet needs to be kept in or out while the door is open, you are not relying on the door to exclude outside animals, and the heaviest pet’s weight and the broadest pet’s chest both land inside one published tier. Under those conditions the manual doors in this group publish more about weather and warranty than the electronic ones do. The Endura Flap states a dual-layer flap that traps air between panels, a magnetic seal on three sides, flexibility to -40°F, and resistance to 50 mph gusts. The Ideal Ruff-Weather states dual vinyl flaps with a 3-inch air pocket between them. The Freedom Aluminum uses a single tinted magnetic vinyl flap with weather stripping, and PlexiDor describes its flap only as acrylic.
Warranty terms range from one year to lifetime. Patio Pacific offers a lifetime residential warranty on the Endura Flap and 3 years for commercial kennel use. PlexiDor’s current homepage states 10 years, though older third-party listings cite 5. Sure Petcare and PetSafe each state 3 years on their microchip doors. Ideal states a one-year warranty on all its dog and cat doors, and no warranty figure was retrieved for the SmartDoor Large, the High Tech Pet door, or the Freedom Aluminum.
The manual flap stops being enough the moment you want the door to make a decision. If that decision only ever concerns a cat or a small dog, the microchip doors make it without a collar. If it concerns a dog too big for the Sure Petcare door’s 7.5 by 6 11/16 in opening, you are choosing between a collar tag on every pet and no selection at all.
