This is a 135mm Bombers bit, Eggbutt Ultra Comfort Lock-Up. It's a used bit, kept in storage for about a year. While it has the characteristic rust, this is a feature of the bit and it can be used without any problems. It's an eggbutt type, which is stable in the horse's mouth. It's suitable for horses with sensitive mouths that are stressed by the bit moving around. If it feels a bit large, you can adjust it by using bit guards. With 5mm thick guards, you can reduce the size by 1cm. Search for "Bombers Bit" to find useful information. Please take a look.