app/views/admin/merchandise/prototypes/_property_form.html.erb
<% @all_properties.each do |property| %>
<div class="property_form left span-9 last">
<% checked = @prototype.name && @prototype.properties.include?(property)%>
<%= check_box_tag "prototype[property_ids][]", property.id, checked %>
<%= property.display_name %> (<%= property.identifing_name %>)
</div>
<% end %>