Serfas' new Stem Clamp Bag System is intended to allow riders to easily carry and access cell phones and other small items.
The system includes several types of attachements, including a small hard case, a large Carry All Bag, two phone case models and more.
The phone cases range in MSRP from $20 to $40, while the larger cases range from $24 to $50.
Source:
http://www.bicycleretailer.com/new-products/2013/03/20/serfas-introduces-stem-clamp-bag-system