Bill
Parkside branded tools can be a bit of a mish-mash. The accessory kits and airline proper components are almost always 1/4 BSP. In both taper and parallel versions. Don t expect all of them in any kit to be the same. I have one with kit with lost of useful parts and adapters that has taper males but parallel females. Nice roll of PTFE tape included for obvious reasons.
Threads into tools can be either metric or UNF. If metric 10 or 12 mm in 1 or 1.25 mm pitch. If UNF 7/16 or 1/2 by 20 tpi.
Seems to depend on what the maker had the line set up for. I ve seen apparently the same tool offered at different times use different threads for the screw in fitting.