<?php woocommerce_wp_checkbox( array(
                        'id' => '_wc_security_deposits_enable' ,
                        'label' => __( 'Collect security deposit' , 'woocommerce-security-deposits' ) ,
                        'description' => __( 'Enable this to collect a security deposit for this product' , 'woocommerce-security-deposits' ) ,
                        'desc_tip' => true ) );
                    ?>

public function process_product_meta( $post_id ){
        $product = wc_get_product( $post_id );

        $enable_security_deposit = isset( $_POST[ '_wc_security_deposits_enable' ] ) ? 'yes' : 'no';

        $amount_type = ( isset( $_POST[ '_wc_security_deposits_amount_type' ] ) &&
            ( $_POST[ '_wc_security_deposits_amount_type' ] === 'fixed' ||
                $_POST[ '_wc_security_deposits_amount_type' ] === 'percent' ) ) ?
            $_POST[ '_wc_security_deposits_amount_type' ] : 'fixed';

        $amount = isset( $_POST[ '_wc_security_deposits_deposit_amount' ] ) &&
        is_numeric( $_POST[ '_wc_security_deposits_deposit_amount' ] ) ? floatval( $_POST[ '_wc_security_deposits_deposit_amount' ] ) : 0.0;

        if( $amount <= 0 ){
            $enable_security_deposit = 'no';
            $amount = '';
        }

        $multiply_by_persons = isset( $_POST[ '_wc_security_deposits_multiply_per_persons' ] ) ? 'yes' : 'no';
        $multiply_by_quantity = isset( $_POST[ '_wc_security_deposits_multiply_by_quantity' ] ) ? 'yes' : 'no';

        $product->update_meta_data( '_wc_security_deposits_enable' , $enable_security_deposit );
        $product->update_meta_data( '_wc_security_deposits_multiply_by_quantity' , $multiply_by_quantity );
        $product->update_meta_data( '_wc_security_deposits_amount_type' , $amount_type );
        $product->update_meta_data( '_wc_security_deposits_deposit_amount' , $amount );

        if( $product->is_type( 'booking' ) && $product->has_persons() ){
            $product->update_meta_data( '_wc_security_deposits_multiply_per_persons' , $multiply_by_persons );
        }
        $product->save();

    }