Our fur babies need some relaxing too! The Black Volcanic Diffuser Charm is the perfect way for your pup to find their inner Zen. Naturally made from black volcanic rock, the charm on the lava stone gives a little fashion flair to our fur babies while diffusing their calming oils. Choose the charm and stone of your choice. Although they are considered to be of stone, they are very lightweight! Square: 13x13mm Round: 14mm The split ring is 10mm and a total length of approximately 1 1/2" inches. Hang the charm on their collar and apply calming oil to lava stone.