● 1/4"&3/8"1/2" O.D. pure copper pipes for superior thermal conductivity● With better tensile strength it withstands high pressure● Embossed polyethylene film heat-resistant foam and thickened cotton for 3-layer insulation● The film provides a robust barrier against environmental factors● Heat-resistant foam protects against heat loss● Thickened insulating cotton adds an extra layer of protection● Achieve M1 flame-retardant and provide excellent thermal and sound insulation● It complies with ASTM standing strong at temperatures as low as -40 ℉● Compatible with different split air conditioners (not included)● Simply unfold cut and solder the pipes for easy connection● Serve as extension pipes● 2 removable protective caps are included