Neatly residing within the seatpost, seat tube, or down tube of your bike, the Shimano SH BTR2 Di2 Battery is a slick alternative to the external mounted SM0BTR1 67 Battery if you're riding with Shimano's next level Di2 electronic groupset. Not only does the internal placement of this battery clean up the aesthetics of your Di2 equipped bike, but it also offers extra protection from nasty weather and road grime. Moreover, you'll appreciate the 15 gram weight reduction with this battery over the external version, especially if you're running it on your race bike. Other than its slick interior placement, the battery remains essentially unchanged, with a fully sealed, 7. 4 volt lithium ion rechargeable unit delivering the same battery life as the external version. In fact, you'll find the Di2 battery lasts anywhere from 600 to 1,500 miles between charges, averaging somewhere in the 1,000 mile range. Shimano recommends charging the Di2 battery once a week if you're a daily rider. Plus, you'll appreciate the battery's 300 charge cycles before it loses any charge holding integrity, meaning it'll last approximately six years if you're charging it once a week. Please note that the Shimano SM BTR2 Di2 Battery needs complementary parts for charging. You'll need Shimano's new E Tube Cockpit Junction Boxes either the SM EW90 A with three ports, or the SM EW90 F with five ports, plus the new SM BCR2 battery charger. Both junction boxes feature an external charging port for connecting Shimano's SM BCR2 battery charger. And like the previous version, the SM BTR2 Di2 Battery takes approximately 1. 5 hours to fully charge. This internal Di2 battery comes with seatpost assembly mounting hardware. Pinarello makes a Seatpost Internal Battery Mount sold separately for Di2, fitting its Dogma 60. 1, Dogma 2, and Dogma 65. 1 seatposts.