If your gate is from a different manufacturer, let us know in the comments, and we’ll do our best to determine which bolt is best for your gate.
If you want to determine the correct size yourself, you can measure the holes where the screws go into the wall. This screw fits nicely into a hole about 7-8mm in diameter because it is about 6.6mm in diameter. Similar to M10 screws, M10 screws are about 8.6mm in diameter, so they are perfect for 9-10mm holes. Some gates use more or less these sizes, but simply choose the right spindle rod size, and you can match virtually any gate well enough to work well.