134a to r12/r22 male coupling

I have a R12/R22 vacuum pump that I want to use with my new set of 134a gauges to pump down auto a/c systems. It would seem to me I need a male coupling to
hook up the 134a gauges which is female to the female (think 1/4") connection on the vacuum pump. So do they make a coupling in those sizes and if so what size should I say for the coupling. Better yet who or where can I purchase the coupling?
thanks in advance for your help
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