I bought the 52"×36" size as potty training pads for my Silky chickens (which are incontinent when young but can be trained as they grow,
much like puppies) and the thick vinyl underside provides a leak-proof guard against the surface on which it's placed, whether it be a floor, chair or bed. The upper layer is also strong and thick, but much softer so would not be uncomfortable for a person.

I washed both pads in very warm water (permanent press cycle) and dried them for 30 minutes on medium heat (with dryer sheets to prevent wrinkles or electric shocks from the vinyl which wouldn't be very encouraging to my chicks) with no evident shrinkage or tearing afterward.
If anything could tear the top layer, chicken claws - much larger than you would expect because they're hidden by feathers - would surely do so, but the pads remained unscathed by their beaks & claws.

I like the large size - it increases efficacy - and soft upper layer, along with getting two so that one can be washed while the other is in use. If you need to replace one daily, however, I would recommend buying a package or two of four pads.

This is a great waterproof pad for the price, far more effective (and similarly less expensive) than the disposable ones I tried before, which fall apart quickly and work poorly due to the cheap plastic not exactly "waterproof" layer topped by a readily ripped & shredded upper layer. These are the same pads they use on all beds in hospitals for a reason. They're almost indestructible.

If you're using disposable pads now and need them constantly, I suggest trying these instead if you have a washing machine, or buying 8 if you don't but need to use a laundromat. Seven large pads would fit into a side-door washer.

In any event, the large pads offer much more security against leakage and are sturdy enough to be well worth the expense regardless of your reason for needing waterproof pads. I highly recommend these waterproof pads.