Rifled copper tubing with enhanced aluminum fins. Immersion-tested at 500 psi, then nitrogen-pressurized and sealed. Left-hand refrigerant and plumbing connections. Liquid line - 3/8" ODS, suction line - 3/4" ODS on 1-1/2 to 3 ton & 7/8" ODS on 3-1/2 to 5 ton units. Liquid line Schrader valve for hiss-testing. Heavy duty polypropylene drain pans. Drain connection: 177L pans have single LH 3/4" FPT, 195L pan have quad drains have 3/4" FPT. Condensate drain elbow and flexible drain tubing included. Downflow plate kit included. AHRI certifiable with all brands of A/C and heat pump systems. ETL listed for use with R-410a when proper metering device is used.