*Why "D4"?  I generally get questioned,  and gets jumbled with A5 (which can be a climbing grade), and D5 (which stood for "Deuce5"), two models I happen to be involved with previously.  My nickname in Yosemite was "Deucey", coined by Grant Hiskes  who mangled my Friesland ancestral name "Middendorf" to "Dusseldorf",  and Deuce4 is my recent "