Shakespeare Galaxy 5228 8' Heavy-duty Extension Mast [5228]Galaxy Style 5228 8' Heavy duty Extension Mast Constructed of high quality Shakespeare white fiberglass, and finished to match Galaxy antennas. This 1 1 2" diameter extension mast can be used to increase height of an antenna and thus improve effective range, or to boost placement of an antenna above on board obstructions. IMPORTANT! If the combined length of your antenna and all extensions is more than 8', users MUST use an upper support bracket