Bright orange high visibility cable balls make TallTower guy wires more visible to aircraft and farm machinery. Balls should be installed on each guy wire 3 m (10 feet) below the guy ring on the top set of guy wires. An additional set of balls can be installed lower on the same guy wires at least 3 m (10 feet) above highest point vegetation is likely to reach. Kit includes 4 balls of 21 inch diameter (53.34 cm) and installation hardware. The kit can be assembled using a phillips (+) screwdriver and 3/8 inch and 7/16 inch sockets. Note that cable marker balls add some wind load to a tower. The added wind load does not significantly affect tower performance under normal conditions. However, the marker balls can accumulate ice which can add significant loads to a tower. The NRG 60 meter HD is the best choice if marker balls are required in an icing environment. Of course, even this tower would be subject to the extra loading; overall survivability is somewhat compromised for any tower in extreme conditions. Sold for use with NRG TallTowers Only