Need to specify a menu

Ive added a search bar to my navigation menu by placing this in my functions.php:

add_filter('wp_nav_menu_items','add_search_box', 10, 2);
function add_search_box($items, $args) {

        ob_start();
        get_search_form();
        $searchform = ob_get_contents();
        ob_end_clean();

        $items .= '

<li>' . $searchform . '</li>
';

    return $items;
}

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The problem is that i have two menus on my site, and the search box shows up on both menus. Is there a way to specify which menu? Ive searched google and most of this forum with no luck. Thanks.

My site is
GearMoose
i’ve deleted the code for now until i can find a solution.