‎2.4 inches

🦎【Generates Heat & Healthy Light for Reptiles】The Heat Warm Clamp Lamp with Switch is the perfect addition to your reptile’s terrarium during fall and winter, This 5.5" diameter, reflective lamp is made of heavy-gauge, painted aluminum. Its integrated ceramic socket can be used with incandescent bulbs, ceramic heat emitters and compact fluorescent bulbs, up to 100 watts. And the spring-loaded swivel head clamp securely attaches to the rim of any terrarium. 🔆【Adjustable Dimmer and Timer Switch】This Basking Spot Lamp with the ability to dim or light up the bulb, 4 light modes you can choice, just press the +/- button the temperature can be adjusted according to needs. It also has a timer function, set to a specific amount of hours like 2,4,or 8 hours, very convenient to use. A great heat lamp for reptile and amphibian terrariums, such as turtle, frog, chameleon, iguana, gecko, bearded dragon etc. 💡【Reptile UV Bulb】The clip lamp comes with two high-quality 50W bulbs, which has UVA/B that simulate sunlight, the ceramic heat emitter for use in standard E27 lamp base and easy to install. Suit for the normal growth of the reptiles and disease prevention. WARM TIPS: the surface temperature of the ceramic lamp is generally high, please keep an appropriate distance from flammable materials and pets, so as not to cause serious consequences.