Actual length of this tube sleeve is 45.5 inches. The total length of the tubeguard, including 1.25 inch end caps, is 48 in. T5 HO tubeguards 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. T5 tubeguards are also NOT recommended for use with dimming systems or applications in which power surges or spikes can cause arcing or over-burning of lamps.