The RD-545 HR is the successor of the RD-545 scale. The difference is that the RD-545 HR can also measure heart rate to provide a more comprehensive picture of body analysis and health. The RD-545 scale does not have this feature.
In 2021, we replaced all RD-545 scales for the RD-545 HR scale and no longer sell the RD-545 scale ourselves. The RD-545 scale will still be sold by some distributors until this stock runs out at these distributors. Both scales have the same look and are the same in terms of functionality.
On the product page of the RD-545 HR scale, you can find all the features and specifications: https://tanita.eu/rd-545hr.