This is the battery that BMW recommends for my bike. Sierra's price was the same or better than all other legit vendors and then they offered 10% off and free shipping on top of that making it by far the best deal out there. I can't quite figure it out, but it looks like I didn't pay sales tax either. I was a little concerned when it arrived via USPS in nothing more than the thin box that the battery came in from the factory with no other packaging or padding, but the battery seems to operate fine. Very happy!
Typical Shoei quality with a few new upgrades. I'm happy with the helmet and I found a discount code which made the price much better than $850, win win. I did have to wait over a month to get it. Nothing on the site said "Preorder" or "Back Ordered". After 2 weeks I inquired as the delay and was told it was out of stock and they were getting it in 6-10 days and then ship to me. I'm happy with the purchase and the price, thank you Sierra BMW.
No need to add a secondary trickle charger cord to the battery, this cord plugs directly into your BMW port. Will usually last upwards of 10 years before the male prong attachment gets worn out.