https://extensions.joomla.org/extension/extension-specific/virtuemart-extensions/multiple-customfields-filter-for-virtuemart/?com_jed_review_5560_limitstart=40
Multiple Customfields Filter for Virtuemart, by usovdm - Joomla Extension Directory
Version 3.0 support Virtuemart 3.0.x + Joomla 3, 2.5. Version 2.0.7 support Virtuemart 2.0.x, 2.6.x and Joomla 2.5
joomla extensionmultiplecustomfieldsfiltervirtuemart