First; There is NO 100% safe way.
Careless package handlers can destroy absolutely anything devised by man to foil them, and they don't honor insurance claims in most instances. Actually, I've never had a UPS claim satisfied, ever!
I have found that in the actual cabinet is the best.
I used to like to have a pair of them bolted together in a box tightly filled with styrofoam and/or bubble wrap, but I had an experience with some SRO's that negated that theory. Box intact, hardly battered, cast frames shattered inside. Like David freekin' Copperfield did it, absolutely amazing.
I’ll send you pics, Joe. I should donate them to the Ripley’s “Believe it or Not” museum.
Jammin’ Jersey packs the drivers tight, and insulated with corrugated cardboard, probably 1.5” all around, in individual boxes. Then they pack the individual boxes tight into one double walled shipping box.
As I said, I’m sure they could get destroyed, but IMO they do it right.
I realize that Jan_68_100s only needs one driver, but I've only ordered them in pairs or quads. I would assume they have a method for sending one that is equally safe.