Comet CA-SPR Mobile Antenna Springs are a must if you are a first responder using one of their Comet CA-2x4SR or CA-2x4SRNMO search and rescue antennas. They are also great for non-emergency off-road use or in areas where a flexible antenna would be a better choice. These spring kits replace the lower antenna rod with a shortened rod and a flexible, durable spring to protect your mobile antenna from many hazards that would otherwise cause antenna damage. You never know what terrain you'll be traveling next.