AEA Can some Zeus owners tell me what this part is for??

Hi guys

just got my zeus .68 cal today- its a german limited version but all the full power parts are included in the bag.. so besides the large transfer port and there is this one part that i have no clue where it goes..

i think it goes inside the regulator to open it completely? to have it unregulated?

and second question- what is the max safe pressure i can set my regulator to?

right now its set at 150bar..

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