Maybe one of these similar products would be of interest:-

Self-Heating Thermal Pet Pad, Cat Blankets for Indoor Outdoor, Pet Pads with Removable and Washable Cover, Self-Warming Winter Pet Bed Mat Blanket for Cat Rabbits Puppies Kittens 60x 45 cm

60 x 45cm Self Heating Pet Blanket Pet Pads without Electricity Winter Warm Pet Bed Mat Pet Heating Pad Dog Mat Washable Cat Blanket Self Warming Cushion Mat for Pets Puppy Kittens Rabbits (Beige)

SUOXU Cat Bed Self Heating cat cushion Pet Pad Blanket No Electric Self Warming,Plush Cat Sleeping Heated Bed Non Slip Machine Washable Warm Mat for Indoor Outdoor Cats,Dogs,Rabbits 60x45cm