How many light sets can I connect end to end?

Under Writer's Laboratory (UL)sets the standard for the number of Christmas lights that can be connected end-to-end. The new UL standard provides that a total of 220 watts may be connected on one 15 amp circuit. Generally, each LED light bulb on our light strings is about .05 watts. The description for each product includes the specific number of sets of that product that can be connected end to end.