The F54T5 fluorescent lamp protectors are profile extruded in a clear, unbreakable Polycarbonate material that provides maximum lamp protection with minimal interference to lamp light output. The 54 watt T5 lamp generates a substantial amount of heat and when used with a tubeguard, that heat must be efficiently dissipated from the lamp.<br /><br />This NEW F54T5 tubeguard has a 15/16” diameter which is larger than its F28 cousin. It also has a new “vented” end cap which allows for the needed heat release. In addition, there's room for a layer of inside air to absorb heat from the lamp and cool it slightly before making contact with the inside wall of the tubeguard. This results in a substantial tubeguard surface temperature drop.<br /><br />This NEW F54T5 tubeguard successfully addresses two major factors that standard tubeguards don’t - the temperature inside of the tubeguard and how close the lamp is to the surface of the tubeguard.<br /><br />Please note: It is not recommended using a tubeguard under any condition where surface lamp temperature can exceed 200 degrees F or in an enclosed fixture where normal heat venting is prohibited. Tubeguards are not recommended for use with dimming systems or applications where power surges or spikes can cause arcing or over-burning of lamps. Only use tubeguards in conjunction with electronic high efficiency ballast that is designed to prevent overheating of the lamp during use and at “End of Life”. NO WARRANTY or GUARANTEE.