I was researching barrel attachments and i just need some clarifications. CW and CCW are straight forward enough, i think

. My understanding is that 14mm is the standard
diameter of the threaded part of the the attachment and the negative (-) attachments have the threads
recessed into the point of attachment (in essence, a "female" attachment) and positive (+) attachments have the threads
protuding out of the point of attachment (in essence, a "male" attachment).
Please correct me if i'm wrong.
Thanks in advance!