This add is for a set of (4) Solid-State Blue LED Lamps in this Illumination Kit you will need for your L7 Amplifier Note: I also have Blue LED kits for the 7-Line and 4- Line of RL Drake Radios. Please see my other listings.The kit includes:(4) LED Lamp AssembliesThe L7 amplifier uses four (4) older style T3-1/4 lamps running off the power tubes 5VAC filament transformer. These LED lamps, are a direct plug-in for the original L7 light bulbs. I also have these Lamps available for the rest of the Drake line of radios, in my other listings and on my web site. Drake has used blue filters since the days of the 4-Line equipment. This continued into the later 7-Line equipment including the TR7(A) transceiver and R7(A) receiver. The problem occurs in later years when the blue filters begin to change and the displays end up looking green. Since the meter and frequency displays are illuminated by incandescent lamps they emit a glow that leans toward the red end of the emission spectrum. Thus a blue filter being back lit by a yellow/red glowing filament will naturally result in a greenish illumination. In the past people would replace the blue filters with newer and perhaps darker blue filters. This was a step in the right direction, but you are still stuck with a light bulb that will eventually burn out and require replacement. In the TR7 transceiver the bulb that illuminates the analog frequency display requires the removal of the DR-7 digital readout board to access the bulb. This is not an enjoyable job and has the potential of damaging the DR-7 or other parts in the radio if the deinstall and install procedures are not followed closely. You will often see the analog display dark as the user never bothered to change a burnt out bulb.Another problem area with the 7-Line equipment illumination is that Drake used small round glass #53 bayonet bulbs. Due to their small size they can not illuminate the total coverage area of the meter or analog display evenly. You will have light and dark areas.To solve both the aforementioned shortcomings we have developed a Blue illumination kit for most of the RL Drake Gear.