This piston kit from MITAKA is a great fit for Yamaha TZR125/250 1KT-B with a bore size of 56.90mm and a 0.50 oversize. It is perfect for those who want to upgrade their engine performance. The kit is made in Japan and is specifically designed for motorcycle enthusiasts who are looking for a classic part to enhance their bike's performance. The kit includes all the necessary components required to install the piston, including piston rings, gudgeon pin and circlips. This makes the installation process easy and hassle-free. The brand MITAKA is highly reputable in the market and is known for producing high-quality piston kits that meet the needs of their customers.