Charity sportive event.  From the website:

“The Trossachs Ton offers the mighty Double Duke; two ascents of the Dukes Pass on the Champion route. It’s one of the best ride outs in Scotland in an area of outstanding beauty with mountains and forests, making this bike ride such a pleasure despite the hills.

Starting out from Stirling with a choice of two distances, the Classic 75 mile route offers a nice ride with Crow Road and a single Duke pass whilst the Champion route at 106 miles is ideal if you’re an experienced Sportive rider.

Expect a great day in the saddle raising funds to help sick and disabled babies and children on this cycling event with first class support throughout the day.”