Learn Russian: Это хороший продукт.

The introductory word это ("this is" or "these are") doesn't change! However, the adjective and noun do. Because продукт is a regular masculine noun ending in a consonant, we add -ы to make it plural: продукты. The adjective also changes to its plural form: хорошие. The final sentence is Это хорошие продукты.

Why doesn't это change to masculine to match продукт?

In this sentence, это is acting as a fixed introductory word meaning "this is". When introducing something, это stays exactly the same regardless of the gender or number of the noun that follows. If you wanted to say "this product" (as in "this product is good"), you would use the masculine pointing word этот: Этот продукт хороший.

Why does the masculine adjective хороший end in -ий instead of the regular -ый?

This is due to the famous Russian "7-letter spelling rule." After the letters г, к, х, ж, ч, ш, щ, you can never write the letter ы. Because the stem of хороший ends in ш, we must swap the standard -ый ending for -ий.

Can продукт refer to any kind of product, like a tech gadget?