Moddog Blech oben
Screw the tool into the 510 connector until it touches loose. Then tighten with the round nut.
To release, hold the round nut with pliers, insert a 4 mm Allen wrench into the top and turn half a turn clockwise to release the round nut lock. You should then be able to unscrew the 510 tool from the 510 connector without any problems.