Accuracy: 0.013mm.Made of high grade spring steel.We ship all the items with tracking number. We do combined shipping, You can use cart to calculate the combine shipping cost. Usually the Item will be shipped within 2 business days after payment completion, the tracking info/numbers are listed in the transaction "details". Please allow 10-20 working days for the product arrival from China. (Depend on the local delivery on your country; some of the location may require more days). We couldn\'t control the item delivery on time. If you have any questions please feel free to contact me. Thanks for looking and please check out our other items.