Outdoor Picnic Blanket with Waterproof Backing 58 x 53 London Plaid. This cozy picnic blanket is durable and roomy enough to enjoy with friends. It has a waterproof backing and attached case with hand grip and adjustable shoulder strap. The top is a soft fleece in a variety of attractive designs. Size 58 x 53 when open and a compact 13 x 10 x 4 when folded.