All returns require prior authorization which you can request by filling out this form. We will respond via email with an RMA # and return instructions within 2 business days. Our return policy for calculator models 6256 and 6258 is:
Models older than 6256 haven't been sold by us in over 5 years and are handled the same as units purchased 5+ years ago.
If you have questions please contact us at returns@1stepmetric.com