Schwalbe Winter studded tryesArvosana 5/5
I have had these several times with different bikes. These are the 240 studded ones and have excellent grip. You can rely on them but still always need to take care when on black ice. Wear gloves to put them on and take your time.
I would recommend these. The Price on verkkokauppa was the cheapest at the time.
John Cottam