That is the sedan AC bracket. A good choice for an SL if using a rotary (Sanden) compressor. Using this bracket will require either mods to the bracket or an upper thermostat housing from a W108 with a taller neck. Using this bracket allows keeping the alternator in the original location as opposed to the Frigiking bracket that moves the alternator up and puts the compressor in the space of the original alternator location.
