additional fields in Specifications

-- HikaShop version -- : 5.1.10
-- Joomla version -- : 5.1.2
-- PHP version -- : 8.1

Hello. First I would like to thank you for a great product. Very glad I found it.

Now a question: how to add new fields to the specification. I would like to add specific parameters for our products.
material
blade width
shaft port
and others.

Thank you very much.