Module only on product detail page

I created a custom html module that I only want to show on my product detail pages. I have assigned them to the menu items of the product list from the category so of course it is showing when the list of all items in that category are showing. I want it only to show when someone clicks to the detail of the product.

I found this post and tried the solution but when I did it ended up hiding the module entirely. Not sure if there is a new way to do this since this post was over a year old.

Any pointers as to how I might be able to achieve this?

Here is the code from my index

<div id="extra1">
<?php if(JRequest::getVar('ctrl')=='product'&&JRequest::getVar('task')=='show'){ ?>
<jdoc:include type="modules" name="extra1" style="xhtml" />
<?php } ?>
</div>

I tried it without the "if" and then the page went completly blank so I put it back in. Yes I did have a slot in my template as well as the module assigned but I decided to select all the parent categories instead of just the sub menu item as I had it set before and now it is working as expected. Not sure why that would affect anything at all but it is working for me now. Many thanks.