HQRP® External Antenna Help boost the GPS signal of your GPS device when it is difficult to get a clear line of sight with the GPS satellites in the sky. This small external active antenna acts as an extension of your existing GPS receiver and can be mounted on the dashboard in your car or anywhere else up to 96.5 away. It will also work with any GPS receivers with BNC antenna connector! Also Compatible with: Garmin GPSMAP 296 376C 396 421 421s 431 431s 441 441s 476C. Disclaimer: This is not an Original Equipment Manufacturer (OEM) product HQRP branded product is a replacement. All brand names and logos are registered trademarks of their respective owners. Any use of the brand names or model designations for this product are made solely for purposes of demonstrating compatibility.