3/4″ & 3/8″ Copper Fittings Kit for HVAC ($2.99-$5.90) 3/4-In. & 3/8-In. Copper Fitting Kit for HVAC: Size: 3/4 In. or 3/8 In. – Application: HVAC – Connection Type: Sweat – Fitting Type: Reducing – Material: Copper $0.00