The ReptiSun Terrarium Hoods are low profile hoods designed to hold one T8 size linear fluorescent lamp. The ReptiSun Terrarium Hoods feature a built-in reflector which allows for deeper penetration of visible light and UVB into your terrarium.Convenient on/off switch. ZooMed new terrarium hood holds 18in Reptisun or Naturesun Linear Fluorescent Light. The hood itself is 20in length.