Ok so far I've done this.
I have an array1 with some products with date such "$product->reference;".
And array2 with:
$get_feature_product = Db::getInstance()->executeS('SELECT id_feature_value, id_product FROM '._DB_PREFIX_.'feature_product ORDER BY id_product');
Now I want to check if every product in array1 have a id_feature_value = 90.
I tried something like "$product->id_feature_value;" but it returns NULL.
When I "var_dump($product);" I can see all this data but don't know how to extract it 
Also I have tried to call function from Product.php, but with no luck.
include ('../../classes/Product.php'); var_dump(getFeaturesStatic($product->id);
Thanks
Tintai