Here's a nice old Davida helmet on ebay...
Hopefully I inserted the link correctly.
http://cgi.ebay.ca/Vintage-flattrack-Davida-helmet-AHRMA-like-Bell-Mag_W0QQitemZ220197562686QQihZ012QQcategoryZ34353QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
Hopefully I inserted the link correctly.
http://cgi.ebay.ca/Vintage-flattrack-Davida-helmet-AHRMA-like-Bell-Mag_W0QQitemZ220197562686QQihZ012QQcategoryZ34353QQssPageNameZWDVWQQrdZ1QQcmdZViewItem