Cal King Size Waterproof Heated Mattress Pad - Patented Electric Mattress Protector Covers Safely and Is the Best. This Premium Cover Is Great for Pets or Kids with Complete Waterproof Protection. 233 Thread Count Soft and Luxurious. Washable electrically heated and waterproof mattress pad. Will not stretch or shrink The ultra-thin wires are 3 TIMES THINNER than conventional warming product wires and, as a result, are virtually indiscernible to the touch. Patented Safe & Warm low-voltage technology ensures even heating throughout with completely safe, non-hazardous operation. From Restonic, winner of eight Consumer Digest Best Buy Awards Pocket depth: 15 inches. Fits mattresses up to 18 inches