Shelf Liner, Cabinet Liner, Non Adhesive Kitchen Plastic Drawer Liner, Non Slip Shelf Liners for Kitchen Cabinets, Pantry, Shelves, Under Sink, Washable Refrigerator Liners (Grey, 12 x 240 inch)

Q: Is this liner a stiff plastic or like a rubbery flex?

I wouldn't call it rubbery. It's smooth but flexible since it obviously rolls up.

Q: can it be used on stairs?

Weatherguard Pro Argyle Charcoal 8.5 in. x 30 in. PET Polyester Indoor Outdoor Stair Tread Cover That’s what I would use . They come in 8 different colors. Would not use shelf liner. It would start to wrinkle up if you didn’t have it tack down properly.