Renata 364 SR621SW Batteries - 1.55V Silver Oxide 364 Watch Battery (2 Count)

Your watch appears to be a 1991 Timex Moon phase reference 19021. This model uses a standard 364 / SR621SW 1.55V silver oxide battery. There should be a two-digit date code on the back you can find on the table here to determine the month and year yours was manufactured. This model is shown on page 18 of the 1991 Timex catalog here.