Must have written it with that disappearing ink. Wanted to thank you for the picture. I drug mine off the shelf and out of the box looking for the female receptacle. Nope mine is a newer cheaper 4221/revision C Has a digital readout and no fancy stuff like yours. Did come up with a link to the railing
http://www.ohiohydraulic.com/store/product203375.html A bit spendy. Thanks Tom