Howdy Tom, In the 1970's and early '80's I imported Prugnat lugs including "Serie 53 V Luxe Dame Mixte (77 degrees) ou Berceau (65 degrees). Still have the drawings. The only difference between the two sets was the different top head lugs. No. 21828 Berceau was twin tube at 65 degree while the no. 21838 Mixte was twin tube at 77 degrees. That 12 degrees accommodates a very tight skirt! Andy Newlands Strawberry Bicycle Portland, OR USA http://www.strawberrybicycle.com http://www.oregonframebuilders.org