Zinc Anode 5/8" Corrosion Grenade # AC Zincs ACZ-5/8

Tubing size is measured on the outside diameter (OD). Copper plumbing is the inside diameter, 1/2" plumbing is 5/8" (OD). This is the size of the suction line on older - smaller central air. Most new installations seem to use 7/8" OD because of the new refrigerant and efficiency standards.

Seems to work great.

I ordered two units to protect my 3/4 copper water pipes but unfortunately even though they are marked 3/4 they are to small to fit the 3/4 inch copper water pipe.