I have the Gerbing kit and use the adapter to fit my battery tender and it works top notch. Be careful with the adapter you buy. there was an issue with polarity not being correct on older model adapters which should mostly be out of circ by now, but you never know. I went to a BMW dealer and he gave me one that is correct.
+1 on the Gerbing gloves - My only regret is that I didn't buy this stuff 20 years ago, but then again they probably didn't make them 20 years ago.
My coldest weather ride to date this year is 4 degrees F in the Catoctin mountains in Thurmont MD and I did not have either the jacket or accessories turned up on the high setting - enjoy