This is a special order item for a Ulysse Nardin deployment strap. 
It is available in a Two or Three piece configuration, when in three piece set you will receive one longer piece and two short pieces each varying by 4mm, this allow for some additional flexibility on the deployment buckle. 

There a several leather and stitching options available from Horween, Natural Veg Tan and a Tuscany hide. 
Please be sure to add a note to your order specifying the strap lengths, take care when measuring your current OEM strap and always measure from pin to pin not the outer edges, this will give you a false size.

How does the three piece strap work ?  Lets say the total length of the OEM strap is 100mm (two 50mm lengths), we take 4-5mm from 50  to give us 46mm as the first length, then we add 4mm to give us a second piece at 54mm and the final piece remains 50mm. What this means is through the combination of the three different pieces we can have three lengths 96mm\100mm\104mm.