Dritech is one of the best available for waterproof bedding. The Dritech 100 Waterproof Mattress Cover is ideal for tackling bed wetting concerns due to toilet-training or incontinence. It does not have that 'crinkly' feel often associated with waterproof covers and is not noisy if you move around a lot in bed.
Single Mattress Cover: 75 x 36 x 7"
Double Mattress Cover: 75 x 54 x 6"
King Mattress Cover: 75 x 60 x 72"