Use Pulsa Bath wet or dry. Its soft, porous spongy texture absorbs soap or lotion making it glide softly on the skin. Pulsa Bath Vibrating Bath sponge is completely waterproof so use it freely in the bath, shower, at the beach, on a water slide or in a hot tub. Its vibrating massage action will invigorate yet relax tired muscles and improve circulation. The diameter is 4.25". 2 AA batteries, not included, provide the thrilling vibrations. Get sudsy and buzz away! Reviews