There is no such thing as a non-binding letter of intent. At the very least, it obligates you to negotiate in good faith to carry out the intended transaction. It can also go much farther than that and, if it contains sufficient material facts, can be the only contract necessary to bind you to the transaction. I don’t recommend that you sign any letter of intent without it being reviewed by knowledgeable counsel, so you should definitely not sign one that contains questionable information.