Oneup components top mount bb chain guidethe oneup components top mount bb chain guide can eliminate dropped chains forever and more than double the life of your chainring at only 34g the oneup chain guide weighs less than a sip of water and will increase chainring durability guarantee performance and can save you money in less than a season doubles the usable life of your chainringas a narrow wide chainring is used over and over it will become worn down increasing the likelihood of dropping