This is a new item.It is a bicycle chain tool. It measures the chain to gauge the wear. A worn chain shifts poorly and wears sprockets at a accelerated rate.on the back of the package is complete and correct instructions on how to use the gauge.please read the back of package before using.We use USPS First Class or shipping.     Thank you. n- need a box number Ask questions - I'm here to help. Please be sure to look over the photos as they are a part of the item's description. Thanks for checking out this listing.  Your Items will be Carefully packed and shipped out.