FYI, for those with the Simms boots, I was advised by a friend who fishes daily that the Chota carbide studs fit and work perfectly in the Simms boots and cost $6 versus $30 - $40 for the Simms.
BTW, use the Search function in the upper left hand corner of this forum and search for common words regarding these boots as there are tons of previous discussions on the matter. Try search words like "Vibram" , "Studs", "Felt", etc.