Charger polarity for Bose SoundLink II??

Hello everyone...
I was given this Bluetooth speaker for my 40th birthday.
Unfortunately for me, after a week of use, I lost the charger!!! :-(

Bose sells this charger for €45.5 (excluding shipping costs...)!!
I'm trying to find an equivalent in a specialized store...

I have the voltage (17-20V), I have the amperage (1A).... but not the polarity!! (very important because if I connect the wrong one I will blow my speaker!!)....

True or false information, or just bad faith: Bose is unable to provide me with the info (for now, but I'm not going to let them off the hook...)!! This is ridiculous!....

Can you please help me?!
For info, the polarity is represented by:
+.)- or -.)+
I don't know if it's specified on the charger (in any case, nothing in the manual, nothing on the speaker, nothing online...
ANYWAY..... TOTAL DEPRESSION!

Thank you all.
Best regards.