1) It is available in 40mm and 44mm.
2) It has Always-On Retina display and Second-generation optical heart sensor with Electrical heart sensor (ECG app).
3) It has 64-bit dual-core S5 processorUp to 2x faster than S3 processor.
4) Watch is available in silver and space grey aluminium.in 3 different colours Silver, Gold, Space-Grey.
5) It offers GPS/GNSS, Compass, Barometric altimeter.
6) It also have biut in Accelerometerup to 32 G-forces, Gyroscope, Ambient light sensor, GymKit and Ceramic and sapphire crystal back.