shopp('product.specs')

This is similar to “The Loop” structure in WordPress for displaying a custom layout for WordPress posts.

Options

All Theme API calls have these options.

return: when set to true, 1, or on, this option forces the tag to return the value instead of displaying/echoing the value to the page. Alternatively, prefix the tag parameter with get to get the same effect. All theme api tags that return a boolean value will return by default.
echo: when set to false, 0, or off, this option forces the tag to display the value to the page. This is the default for all non-boolean tags.
is: when set to true, 1, or on, this option will evaluate the return of the theme api call as a boolean true or false value. See how values are converted to boolean.

<?php while(shopp('product','specs')) { … } ?>

<?php while(shopp('product','specs')): ?>
    …content shown for a specific product spec…
<?php endwhile; ?>