Naturalizer - Auburn Hi Plus (Black Leather W/ Plus Shaft) - Women's: Sleek and sophisticated, the Auburn brings comfort to the workday. Leather upper for long durable wear. Inside zipper for easy on/off. Lightly padded footbed for added comfort and support. Polyurethane sole provides great traction. The simple styling allows you to wear them in both dress and casual situations. "Plus" size shaft is 17 1/2" circumference.
Category reference at Zappos.com:
Women's > Women's Dress > Dress Boots > Dress Boots - Comfort