Lead valve gasket for Giorno SN50 Model is AF24-140-250. Thickness is about 0.5mm. Aftermarket. We use sheets made by Japan Balcar Industrial and are certified by professional shops. Fits Manufacturer Part Number: 1711-GAH-A00/17112-GAH-A00 (Old Model Number: 17111-GAH-000/17112-GAH-000) The color of the material may change without prior notice, but the performance of the product does not change.