Bluetooth 4.0 is a significant advancement in the Bluetooth technology standard. Introduced in 2010, this version is designed to be more energy-efficient and cost-effective, making it ideal for devices that run on coin cell batteries such as fitness trackers and other wearable devices. One of the key features of Bluetooth 4.0 is its low energy (LE) technology. This allows devices to remain connected and exchange data while consuming minimal power, thereby extending their battery life. Another notable feature is its increased range, offering connectivity up to 60 metres, depending on the environment and device capabilities. This makes it suitable for applications that require long-range communication. Bluetooth 4.0 also supports classic high-speed data transfer, along with the new low energy protocol. This means it can handle both small, periodic data transfers and larger, consistent data streams, providing flexibility for a wide range of devices and applications. The version is backward compatible, meaning it can connect with devices that support older versions of Bluetooth. However, to take full advantage of the low energy feature, both devices need to support Bluetooth 4.0.