Terry, I worked for White's, and now work for First Texas. What algeus is talking about is perfectly legit and routine. Any detector with a microprocessor is required, at a minimum, to be tested for radiation emissions and have an FCC Declaration of Conformity. If the TX runs over 9kHz, they have to be tested as an intentional radiator. If they are exported, there are additional certifications required, like CE.
The manufacturer is required to have the paperwork (certs & test results) on file and available. It may be that the Sandshark has never been sold for export, so it may not have a CE certificate, but Tesoro should have at least an FCC DoC. It sounds like that's all Israeli Customs was asking for. The whole thing should have been resolved in 2 emails.
algeus, UL has nothing to do with this. UL listing is normally associated with dangerously high voltages/currents, such as things that get plugged into a wall outlet. I don't know of any hand-held battery-operated detectors that are UL-listed.