(Description from the Magnanni website)

The Peyton II is a smart-casual lace up boot featuring a cap toe. The Peyton II is crafted from supple calfskin leathers and features a supple pebbled leather cuff for style and added comfort, as well as a durable leather sole covered by a protective rubber layer and added TPU inserts.

Magnanni shoes typically size a half size large (see picture with sizing chart and comments from the website). A US 11.5 will fit like a US 12.