Feature: 1. The high gain antenna is a super quality metal antenna, sturdy and durable. 2. Folding telescopic antenna compatible with Garmin Astro 320, 430, 900, Alpha 50, 100, and other portable GPS devices. 3. Provides stable and strong signal reception, extending operational range. 4. Simple installation process; no tools required—install by hand easily. 5. Equipped with direct SMA connectors for Garmin Astro and Alpha series. Compatible with standard SMA ports on Astro and Alpha devices. Specification: Item Type: High Gain Antenna Material: Metal Compatible Model: For Garmin Astro and Alpha handheld GPS devices Folded Size: Approx. 21.7 cm / 8.5 in Extended Size: Approx. 127 cm / 50 in VHF Frequency: 136–174 MHz Gain: 3.0 dBi How to Use: This antenna extends communication range. Simply attach the telescopic antenna by hand. Features direct SMA connection for Garmin Astro and Alpha series. Suitable for Garmin Alpha 50, Alpha 100, Astro 320, 220, 430, and 900 handheld units. Package List: 1 x Telescopic Antenna