When upgrading to a radio from a radio that did not have GPS, a GPS antenna will be required if the vehicle doesn't have one factory. The multiplexer is a great option, as it will combine both XM and GPS to fit to a single port if the radio uses the same port for both. Usually this Fakra port is Curry (yellow). This is a kit to provide GPS, and optional to add an XM antenna if the vehicle doesn't have one. It uses a splitter to utilize both antennas.
Mostly this is great for the TIPM vehicles that upgrade to a mygig for navigation, but it also works for many other radios just fine. The XM antenna, if opted for, will need to have sky access, the GPS antenna is fine inside the dash facing up (without metal above it). Generally only FCA (Dodge Jeep Chrysler RAM) would use this, as it's the only manufacturer that combines the XM and GPS with some radio systems.
Perfect for 2009-2012 RAM trucks, 2008-2018 Wrangler JK's, 2008-2014 Dodge Challengers, 2008-2018 Dodge Grand Caravan.
SKU for GPS antenna and splitter (multiplexer): U-KITSXM-GPS
SKU for GPS antenna, splitter (multiplexer) AND XM antenna: U-BDLSXM