Custom post type only store 10 post only

i create a custom post type with ACF fields for my slider but everytime i query my custom post type it only shows 10 post even though i have more (like 14 post) and if i add more it just replace the other.

Here’s my code :

function custom_slider_post_type(){

    $args = array(
        'public' => true,
        'supports' => array('title', 'thumbnail'),
        'labels' => array(
            'name' => 'Store Images',
        ),
    );

    register_post_type('slider_image', $args);

}
add_action('init', 'custom_slider_post_type');

and this is my query:

$slider_images = new WP_Query(array(
        'post_type' => 'slider_image',
        'post_per_page' => -1,
    ));

    if($slider_images->have_posts()){
        $images = array();
        $checkAll = array();
        while($slider_images->have_posts()){
            $slider_images->the_post();
            $parent_sections = get_field('parent_section_field');
            $image = get_field('homepage_banner');
            $product_link = get_field('products_link');
            $checkAll[] = array(
                'image' => $image,
            );
            $show_in_beauty = false;

            if($parent_sections){
                foreach($parent_sections as $parent_sections){
                    if($parent_sections->post_name === 'beauty-products'){
                        $show_in_beauty = true;
                        break;
                    }
                }
            }

            if($show_in_beauty){
                $images[] = array(
                    'image' => $image,
                    'link' => $product_link,
                );
            }
        }
        var_dump($checkAll);
        print_r(count($checkAll));

Solved: i forgot to add s in 'post_per_page' => -1,