bulkhead sizes...

what size bulkheads r needed for 1 3/4" hole? i have a bulkhead, not sure what size it is considered… it’s little over 1 1/2" od but uses 1" pvc fittings inside. so what size is it? 1 1/2? or is it considered 1"??

I think 1" but idk

dammit ian!!! lOl
i need to order 3 more of these and not sure if i need 1 or 1 1/2

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u r the man!!!