The heel especially. I've worn my Chippewa 7"ers in Oxblood with office-wear, and it works fine. The heels are not quite a block, but much less shaped than my Red Wings. Definitely the flatter shape that you'd more likely see on a British motocycle boot like anything in the Lewis/Aviakit range would be more subtle tucked under trousers. Equestrian boots seem to have had an influence on motorcycle boots on both sides of the Atlantic. The British boots directly were based on hose riding boots (again, see the development of the Lewis boots especially), with the lower heel that those tend to have in the UK. The American Enginer boot definitely has a cowboy boot influence in that heel, even though it was designed for a purpose other than riding to begin with, before being adopted for motorcycle use (and, I'm sure, certaing elementsd evolving as standards for that usage).