I think you will see the tetraflouroethane disappear as it is actualy illegal to vent this gas into the atmosphere... it is a known ozone degrader.
It was used as a refrigerant gas... but no more due to the restrictive licenses and special handeling required.
This is why you see this type of gas duster gas being replaced with Diflouroethane.. it is not a proscribed gas.
Many retailers are not replenishing their stocks of tetraflouroethane,, and some brands that used to be tetra are now diflouroethane.
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