Hello,
Your vase is from the Gardiena series, a range of pressed glass tableware from 1961. The capital S stands for 'Solde' or Sale in English, meaning that for some reason this vase didn't meet standards and was sold at a discount price. There are items that are from the 20ies that are marked with an S as well and that causes sometimes confusion, but it is a different and smaller letter type that is circled and stands for Joseph Simon.