The Bosch PowerMore 250 is only compatible with sizes MD-XL. The PowerMore should only be mounted with the guide rails included with the PowerMore battery. During installation, pay particular attention to the markings on the battery holder and on the PowerMore battery holder. We recommend the 200mm cable to connect the Powermore to the charge port on the lower non-driveside downtube. Size small is not campatible with a PowerMore. Note that the included waterbottle cage included with the PowerMore is not compatible with the LTe.