Summary: I bought a Gigaset S510H pro hand set to replace a broken C47H, which is no longer a current model. Unfortunately the S510H pro did not quite fit the charger on my C475 base: otherwise it was a really good hand set and I decided to change my base to one that the new hand set would fit. Being simple-minded I thought that the appropriate base would be part of the Gigaset 510A set.
Summary: Really impressed with gigaset two phone system which I have owned for about a year. When my sister wanted to replace her phone I was more than ready to recommend Gigaset, so I ordered the trio for her ( the extra handset was useful as she has mobility problems) and she is thrilled with it. Easy to set up, easy to use, thoroughly recommend.