Line sets are the copper tubes that carry coolant, usually R410a at this time, between the outdoor condenser unit and the indoor evaporator unit. All of our line sets come with insulation for maximum performance and protection against minor abrasion or damages. Our line sets all come pre-flared and with brass fittings for ease of installation, and all of our featured line sets are made here in the United States. For added refinement and additional protection, you can cover the insulated line sets with a line set cover kit and won't even know they are there!