One of the advantages to the Original and Original Tuckable Series Holsters is that each one of the 7 sizes available accommodates multiple firearms. 

So if you have, for instance, a Glock 19 and a Sig P239, they both fit in the Compact or "C" holster. 

You can use this Size Chart as a cross reference to see if you can carry more than one of your firearms in the same holster!