Actual length of this tube sleeve is 44.6 inches. The total length of the tubeguard, including end caps, is 45.1 in. T5 HO tube guards are safe to use ONLY in conjunction with electronic high efficiency ballasts designed to prevent overheating of the lamp during use and at end of life. They are not recommended for use under any other conditions including those in which surface lamp temperature can exceed 200 degrees Fahrenheit or in enclosed fixtures where normal venting is prohibited. Field tests are recommended before large installations. Life span varies by application, and no warranty or guarantee is offered on this tube guard.