protected function get_default_query_vars() {
		return array_merge(
			parent::get_default_query_vars(),
			array(
				'status'            => array( 'draft', 'pending', 'private', 'publish' ),
				'type'              => array_merge( array_keys( wc_get_product_types() ) ),
				'limit'             => get_option( 'posts_per_page' ),
				'include'           => array(),
				'date_created'      => '',
				'date_modified'     => '',
				'featured'          => '',
				'visibility'        => '',
				'sku'               => '',
				'price'             => '',
				'regular_price'     => '',
				'sale_price'        => '',
				'date_on_sale_from' => '',
				'date_on_sale_to'   => '',
				'total_sales'       => '',
				'tax_status'        => '',
				'tax_class'         => '',
				'manage_stock'      => '',
				'stock_quantity'    => '',
				'stock_status'      => '',
				'backorders'        => '',
				'low_stock_amount'  => '',
				'sold_individually' => '',
				'weight'            => '',
				'length'            => '',
				'width'             => '',
				'height'            => '',
				'reviews_allowed'   => '',
				'virtual'           => '',
				'downloadable'      => '',
				'category'          => array(),
				'tag'               => array(),
				'shipping_class'    => array(),
				'download_limit'    => '',
				'download_expiry'   => '',
				'average_rating'    => '',
				'review_count'      => '',
			)
		);
	}