134A gas
 

i want to know where i can get a 134A gas tank(CANADIAN DEALER PLEASE)

Are you looking for the actual refrigerant (industrial tanks) or just normal duster cans? For duster cans, just go to The Source (Radio Shack). The NexxTech (?) brand is tetrafluoroethane 1, 1, 1, 2 (134a gas). You can also look in computer stores, just make sure to read the back of the can before buying to make sure it's tetra-, not difluoroethane.

And get a duster adaptor from ASCA.