The Samsung Galaxy S4 model SCH-I545 is a developer's smartphone specifically built for the Verizon Wireless network and based on the SPH-L720 model. It is also not necessary to root the phone to gain access to all its internal functions. This enables enthusiastic owners to avoid the problems normally present with a root without having to give up all the software that can only be run by a user willing to root the phone. The I545 is thus very popular with the root and mod community since it is easy to work with and can serve as an entry point into the smartphone modding community. Additionally, Samsung continues to support the phone after it has been modified, unlike with normal Samsung phones. The Samsung Galaxy S4 uses a Quad-core 1.9 GHz Krait 300 processor and a Qualcomm APQ8064T Snapdragon 600 chipset, alongside an Adreno 320 GPU and 2GB of RAM. The Galaxy S4 comes with 16GB of internal ROM storage, which can be expanded by microSD cards up to 64GB in size. Only 1GB of the 16GB is dedicated to the operating system, leaving most of the 16GB available for software. The dual-band Wi-Fi 802.11 a/b/g/n/ac antenna is capable of serving as a mobile hotspot in addition to providing internet access to the phone. This enables it to broadcast its wireless connection to other cell phones, smart phones, tablets, and similar devices. The antenna uses UMTS technology and is compatible with the GSM, CDMA, HSPA, EVDO, and LTE cellular networks. The Samsung Galaxy S4 comes equipped with a v4.0 Bluetooth wireless connection that has A2DP, EDR, LE and aptX capabilities. The Galaxy S4 is powered by a removable 2600 mAh battery, which offers about 12 hours of battery life under normal use. The battery can be charged via the phone's USB port or by an external charger. The Samsung Galaxy S4 has a 5-inch Super AMOLED screen capable of displaying up to 1080 x 1920 pixels, which are the exact specifications for full HD 1080p video. The screen supports multitouch. The rear-facing 13 MP,