FESTO 454g AV-20-4 Pneumatic Cylinder Used, 30-day money back guarantee. If there is anything wrong with the item that you have purchased, please contact us directly and give. us a chance to help, we respond quickly and will ensure you are satisfied with your purchase and experience! Please do not leave negative feedback or open any disputes with eBay or PayPal. Contact us directly and we will fix the problem quickly. We strive for 5/5 Star service! Fast & Free shipping!