Its compact design reduces impacts and protects the battery. Having passed the IPX7-International Protection Marking, TANK can protect itself against water immersion, drops and dust, making it suitable for hostile outdoor environments. The upgraded PCBA with max 90% energy-efficiency can reduce energy consumption. Besides, TANK is made of non-toxic silicone materials, and we employed the natural Kraft paper package to avoid excessive package, while using recyclable, economical and environmentally friendly material.