Vintage Seiko watch model from the late seventies, very rare

Very old vintage Seiko brand watch, original model from the late seventies, 100% authentic This is a (Caliber) or movement of Seiko that is very famous. • It was mainly produced from the late seventies to the mid-nineties. • The specific model (6309-5820) is from the Seiko 5 Automatic series. Price negotiable