Carbide Tip * Serger Upper Knife * VacSewCenter provides the best protection to keep your vacuum and sewing machine working in prime condition at all times. * Our 100% satisfaction guarantee ensures that you will be happy with your VacSewCenter purchase. We strive to make sure that all of our customers are satisfied and this is why we offer a 7-day money back guarantee. Buyer is responsible for return shipping. * We strive to make sure that all of our customers are satisfied and this is why we offer a 7-day money back guarantee. Buyer is responsible for return shipping.