Inhouse product
Coiled bare copper tubing (reddish-brown)
Usually packed in:
Plastic wrap or cardboard box
Sometimes labeled “Made in Korea”
Smooth, flexible tube used for AC & refrigeration
These coils are standard HVAC materials with:
Outer diameter: 1/4" (6.35 mm)
Thickness around 0.028" (close to 0.030" standard)
Soft annealed copper (easy bending)