Please note that the packaging indicates that it is a Swimming Pool bulb but, this is the bulb that will work in your Lava Lamp.Product Description Watts: 100W Voltage: 120V - up to 125V rating compatible Type: R20 Base: Medium Base - Regular Household Screw-in Part Used for: Lava Lamps, Spas, Pools Details Length: 3.55" Diameter: 2.5" Watts: 100W Voltage: 120V - up to 125V rating compatible Type: R20 Used for: Lava Lamps, Spas, Pools