Steep terrain calls for excellent traction, hinged bindings, and compact size. If you plan on heading into steep terrain and are on the cusp of the manufacturer's recommended size range, consider sizing down.
These bases called "breakaway" bases are just that, broken apart as the player slides into them making them a good solution to this injury danger. You may encounter problems promoting products on eBay without the support of a good back order system.
Battery life is rated at around 6.5 hours at moderate volume levels, and you get an extra two charges from the case, which has USB-C and wireless charging.