A medium stiffness monofin with room to wear 5mm sock on size 43 feet. I found it to be more comfortable with 3mm socks or even barefoot, but I don't have hardcore monofin feet like some on this board.
[ame=http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=230753320019]Monofin (Triton hyperfin) for freediving and spearfishing | eBay[/ame]
[ame=http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=230753320019]Monofin (Triton hyperfin) for freediving and spearfishing | eBay[/ame]