There is a... or there are five-six weeks lead time

I need to know which one is correct even if I know…there’s (singular) and there’re (plural)
1- There is a five-six weeks lead time.
2- There are five-six weeks lead time.
Thanks for your response.

Good morning Ofelia1014, No1 seems to be far more suitable in my opinion.

The lead time is considered one single unit of time, regardless of how long it may be. ‘Week’ is a modifier here, so you don’t have to worry about number agreement with the word ‘week’.

Therefore, you have to say “There is a five - six week lead time.”

When you’re reading this sentence, you read the ’ - ’ as the word ’ to '.

Alternately, you could say " There are five to six weeks of lead time."