The kit includes:
1. A dedicated Bluetooth remote control: this is another way to trigger the Gear 360 remotely without using a Samsung phone. Please note if you don't have a Samsung phone, you'll still need to stitch the photos and videos, either on Windows with the included Action Director (you'll need to make sure your processor is compatible), on a compatible Mac using bootcamp, or with Autopano.
2. A handle that converts to a mini tripod. The remote control can be attached to the handle.
3. Quick release attachment plus a curved mount and a flat mount.
The accessory kit is currently around $70 from Amazon.
Besides the Gear 360 accessory kit, there's also a dedicated waterproof housing but I still haven't seen it available from a US retailer.