The [RoadX RXFrost Arctic 215/50 R17 91H](%id:2976482%) tyre features a non-directional orientation, meaning it does not have a specific inner or outer side marking. However, for modifications of this product, such as the [RoadX RXFrost Arctic 245/45 R18 100H](%id:2976489%) Run Flat or [RoadX RXFrost Arctic](%id:2976475%) 225/55 R17 101H Run Flat, you may find specific markings indicating the inner and outer sides. [The answer was generated based on the product specifications provided, which indicate that the RoadX RXFrost Arctic 215/50 R17 91H tyre is non-directional. This means it can be mounted on either side without a specific inner or outer marking. The mention of modifications is based on the data that lists other versions of the tyre that may have different characteristics.]