I spent $125.00 on a 3# Halotron bottle. Had to use it once and when I attempted to have it refilled was told thay were no longer supporting this service. Expensive mistake! In addition the paint job on my aircraft suffered where any of the material came in contact with the surface. I had to wet sand with polishing compound and buff out. Bought 5# CO2 for $50. It's bulkier but no problem so far and refill for ten spot. Doug