Route review from sportive.com
Route review from veloviewer
Route review from roadcyclinguk.com
A really detailed report from www.cycling-challenge.com
col des Aravis: 6.7km @ 7% (1.487m)
col de la Colombiere: 11.7km @ 5.8% (1,618m)
col de la Ramaz: 13.9km at 7.1% (1,619m)
col de Joux Plane: 11.6km at 8.5% (1,691m)