The Hi-Tech Lamps part number CFL18SE/841-U is an 18 watt (18W), biaxial fluorescent lamp made by Ushio. This lamp has a maximum overall length of 229mm and a 2G11 four pin base. The average lifetime is 12000 hours. This lamp has a color temperature of 4100 Kelvin (4100K), and has an initial output of approximately 1250 lumens. This lamp can be used with either Instant Start or Rapid Start ballast and is also known as Ushio CF-L18SE/841 and 3000401.