The stems fit Rene Herse handlebars and many others (25.4 mm clamp). They fit on most non-French bikes (22.2 mm steerer).
Note: Nitto NP stems are about 3-4% longer than their nominal size. For example, the 9 cm actually measures 9.3 cm, and the 12 cm measures 12.5 cm.
An optional decaleur (shown in the photos on the right and left) allows you to mount your handlebar bag securely, yet make it easy to take the bag with you when you park your bike.