Shown on this slide is a good quick reference guide. One important aspect is that LSM303AGR is designed to be board compatible with several of ST’s accelerometers which use the 2 x 2 package. This makes it easier to upgrade existing designs to the new features. The LSM303AH is very similar to the LSM303AGR except that it has an integrated step counter and uses the 1.8V rail instead of 3.3V, making it perfect for wearables.