The compact eTrex was introduced in 2000; several models with different features have been released since. The original eTrex, commonly nicknamed "eTrex Yellow", offered a lightweight (5.3 oz/150 g), waterproof, palm-sized 12-channel GPS receiver, along with a battery life of up to 22 hours on two AA-size batteries. It was replaced in 2007 by the eTrex H, which added a high-sensitivity receiver. Other eTrex models include the Summit, Venture, Legend, and Vista, each with various additional features such as WAAS, altimeter, digital compass, city database, and highway maps. Many of these models come in color and expandable-memory versions.