Kneipp Calendula Rosemary Foot Bath Effervescent Pebble 1 Pebble is designed to refresh and soothe tired feet, and is formulated with premium calendula and chestnut extracts, as well as camphor and menthol. The effervescence, combined with rosemary and thyme essential oils, provides a cooling and soothing sensation and is free of preservatives, kerosenes, silicones and mineral oils.