External mic for Navman S70

[Night Rider]

Hello people,
I have just purchased a S70 with Bluetooth. Can anyone help me with an external mic on a 3.5mm jack? The Navman site displays one but not available to buy.....any ideas?

http://www.navman.com/Navman/Templates/productinfo...69030.aspx

Edited by Night Rider on Friday 14th December 14:43