The Box Three shifter makes good use of nylon composites in both top and bottom shells as well as the levers. Box Three is our performance and value tier. So this shifter sheds all the fancy trappings of the top 2 tiers but maintains their shifting characteristics. All Prime 9 shifters take advantage of the 9-speed's inherent durability, simplicity, and reliability. Not only is the shifter mechanism joyfully simplified, but fewer shifts are needed for every mile of travel. And the best part is?  Prime 9 is also terribly forgiving so you won't have to constantly adjust your set-up. Available as a multi-shift (pull several gears at once) or single-shift shifter (a sound choice for e-bikes).