Domestic Long Hair isn't a breed. It's the label for a mixed-ancestry cat with a long coat, the fluffy counterpart of the Domestic Short Hair. These cats come in every color and pattern, from tabby and calico to solid black and smoke, and some look a lot like a Maine Coon or Persian without sharing that ancestry.
With no breed standard, size and personality vary widely, though most adults weigh 8 to 15 pounds. What they share is a coat that needs regular brushing to prevent mats and hairballs. In Irving, where summers are long and hot, that coat deserves attention, because a matted cat can't cool off or groom properly. Spending time with a cat tells you far more than the label does.