Or, if you prefer, Franz Xaver Hüller or F.X. Hüller.
Helen's page on FX Huller is at http://bassic-sax.info/version5/vintage-saxes/european-made-saxes/f-x-huller/
Also, definitely check out the beautiful http://fxhuller.com website.
FX Hüller also made some stencils for Hammerschmidt" and CA Wunderlich. Be sure to check out those pages for some more pics.