The Apple Watch may be one of the most smartwatches around, but it does not have an unlimited battery life. Battery extenders such as the BLOC Power Bank for Apple Watch are designed to let you enjoy your smartwatch for longer. This particular battery extender has a 2000 mAh battery to provide up to 4 full recharges for your watch. It provides you with a 100% wireless charging experience.
The BLOC Power Bank has a 10mm design, so it is compact enough for you to take it with you on the go. It is available in stainless steel, wood, marble, and various other versions. You will have to wait till June to get yours.[Source]