Since being portable is in your criteria there are many to choose from that are air cooled. All are made overseas most in China...even the brand named ones by Benjamin or Air Venturi, Vevor...etc. What is critical is to follow maintenance very well and stop at 300 bar even if it's rated for more. My portable is a Benjamin Traveler...3 yrs old now gun fill only. Do some research here and YouTube and remember there all cheap and the QC from China manufactures is weak. Count on fixing it. Good luck with your selection.