Feature: 1. High-gain antenna of superior quality, constructed from durable metal material. 2. Expandable telescopic design compatible with Garmin Astro 320, 430, 900 and Alpha 50, 100 handheld GPS devices. 3. Enhances signal reception for improved range performance. 4. Simple installation process with no complex procedures required. 5. Equipped with direct SMA connectors for seamless connection to Garmin Astro and Alpha series via standard SMA interface. Specification: Item Type: High Gain Antenna Material: Metal Compatible Model: Designed for Garmin Astro and Alpha series handheld GPS units Folded Size: Approx. 21.7 cm / 8.5 in Extended Size: Approx. 127 cm / 50 in VHF Frequency Range: 136 - 174 MHz Gain: 3.0 dBi How to Use: Improves communication range and signal stability. Attach the antenna by hand using the integrated SMA connector. Suitable for portable use with Garmin Alpha 50, Alpha 100, Astro 320, 220, 430, and 900 series handheld devices. Package List: 1 x High Gain Antenna