The Taos 13 Seer 4AC13 is an environmentally friendly and highly reliable air conditioner. The Taos utilizes a Long-Life-Alloy aluminum condenser coil and the tubing thickness is more than twice as heavy as comparable copper condenser coils. It is both rugged and efficient, and because of its all aluminum construction, the Taos is also less susceptible to corrosion than most other air conditioner condenser coils. All Crown air conditioners utilize aluminum for the coil end plates, in addition to aluminum fins and tube. This mono-metal construction makes for an extremely reliable, corrosion resistant air conditioner.