OVER サブフレームキット Z900RS(21-)

The product you're referring to is the "サブフレームキット" (Subframe Kit) from Over Racing, designed for the Kawasaki Z900RS produced from 2021 onwards.
This type of aftermarket accessory typically aims to enhance the motorcycle's performance and aesthetics by providing additional support or a platform for mounting other components like rearsets or luggage. The subframe kit can improve rigidity, reduce weight, and potentially allow for better handling and stability.
If you're considering purchasing or installing this kit, make sure to check compatibility with your specific motorcycle model and year, and consult the manufacturer or a professional mechanic for installation guidance. If you need more detailed information or specifications about this product, feel free to ask!