create free shipping for one product

-- HikaShop version -- : 3.1.1
-- Joomla version -- : 3.7.2
-- PHP version -- : 5.6

Hi, I'm trying to fix a problem but despite reading the documentation I'm in trouble.
I have set shop expeditions this way:
Shipping costs € 5 for purchases lower than € 40 and free shipping for purchases over € 40
Now I would like to create a product of € 15 but with free shipping, how can I do it?

Qualcan someone help me, please

Hi,

Add that product to a specific warehouse and create a free shipping method linked to that warehouse and that should do it.

Thank you I solved