The SR-F306 is a rubber coated flexible antenna and has a spring base for better flexibilty at the base connection.
It is one of the best reliable antennas on the market.
 
Compatible with Garmin Astro 220/320/430 & ALPHA 100,200,300
 
Lenth: 40cm
 
Gain: 3.5dbi compared to the FLEX V3 2.15 dBi