Honeywell HFO-1234yf is a replacement for R-134a as a refrigerant in automotive air conditioning systems. HFO-1234yf is the first in a new class of refrigerants that has a 335 times lower carbon dioxide content than R-134a (and only 4 times higher than carbon dioxide, which can also be used as a refrigerant but has significantly different properties than R134A, in particular it must operate at about 5 times higher pressure) and an atmospheric life of about 400 times shorter. This product is becoming increasingly popular in 2017 and in many new vehicles. It is growing in popularity and Refrigerant Depot is your first source.