These closures can be used on all automatic bag closing machines and select semiautomatic machines. This allows packagers that have both types of packaging operations to maintain one type of closure inventory. Series J-NRP are medium duty bag closures recommended for packages up to 3 Lbs in content weight. Series J-NRP are available in seven plastic colors. Series K-NRP are heavy duty bag closures recommended for packages up to 5 Lbs content weight. Series K-NRP are available in three plastic colors.