The Shimano BB-MT501 68/73mm Hollowtech II Threaded BSA Bottom Bracket BB52 MT500 is a high-quality bottom bracket designed for mountain bikes. It is made of aluminum resin and features a hollow spindle type for optimal performance. With a shell width of 68mm and compatibility with various Shimano models, this bottom bracket is a reliable choice for cyclists looking to upgrade their bike components. The set includes the bottom bracket itself and is designed for easy installation and maintenance. Its sleek black color adds a stylish touch to any bike, making it a popular choice among riders.