A Ruby is either ee:SS or ee:sS with the latter version yielding the presence of white mismarking in whole color breeding. If you breed ruby to ruby the puppies will all be ruby if both parents are ee:SS. Blenheim colored puppies can appear if both parents are ee:sS. Ruby to Black and Tan will give both Ruby and Black and Tan puppies. A ee:sS Ruby bred to a Tri Color can yield all four colors and a ee:sS Ruby bred to a Blenheim can yield both Ruby and Blenheim colored puppies. A ee:SS Ruby bred to either and Tri Color or a Blenheim will only yield Ruby and possible white mismarking.
Our Cruisin Rubicube pictured on the left is a ruby to ruby breeding.