[ARW VISIONS]

try this..

{if $products[product].extra_fields ne ''}
{foreach from=$products[product].extra_fields item=extra_field}
{if $extra_field.service_name eq "nameofextrafield"}
{if $extra_field.value ne ""}
{$extra_field.value}
{/if}
{/if}
{/foreach}
{/if}
{if $extra_field.service_name eq "nameofextrafield"}button code here{/if}