Our Prayer Box Pendants paired with a Lava Rock will give you a way to enjoy Aromatherapy all day long. Simply add a few drops of your favorite essential oil to the Lava Rock and place inside a Prayer Box Pendant with holes. Attach the pendant to a chain or include in your favorite necklace design to add to your unique style. 10x12mm Lava Rock Heart Diffusers will fit inside the following prayer box/oil diffuser styles - #002, #003, #004, #005, #006, #007, #008, #4, #35, #43, #55, #91, #96, #103, #266, #67, #75, #214, #227, #287, #217. Our 12mm Lava Rock Diffusers will fit inside the following prayer box/oil diffuser styles - #002, #003, #004, #005, #006, #007, #008, #4, #003, #35, #43, #55, #91, #96, #103, #266, #101, #67, #75, #214, #287, #217. Our 16mm Lava Rock Diffusers will fit inside the following prayer box/oil diffuser styles - #4, #35, #43, #55, #74, #75, #101, #287, #217