I have been on CBP website for 4457. It's good that it let's you fill out and then print. ?At the top of form it has Number Field what is that for? Serial # If that's case you can only use form for one item? In description field it says articles or plural. In past I've put a few items on each 4457. I read back instructions and it is no help. All help appreciated!

in the spot you are asking about my agent just wrote N/A

It’s a mystery.

I have left it blank. Customs never fills it in.

Someone told me they plug in the gun’s serial number.

So I have also done that.

Doesn’t seem to make any difference to anyone.

Thanks a lot for the input. You can make it multiple by leaving Number field blank or if you did put ser# in that field it would be for the one item below. On my older ones I have put several items w/ser# on the form in description box. Thanks for the input from all.

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