INTELLIGENT DESIGN: UPS for 4B / 3B+ / 3B. Built-in power path management, supports side-loading and high-current line compensation. Features two USB-A ports and one USB-C output. Provides uninterruptible power to keep your devices running during movement. Streamlined design helps reduce cable clutter. Refer to the link in Product Guides and Documents at the bottom of the page for more information. MULTIPLE PROTECTION: Supports output overcurrent, overvoltage, and short circuit protection; input overvoltage, overcharge, overdischarge, overcurrent discharge protection, and overheat protection. Safe and reliable. USE AND NOTE: This product is a power supply device. Keep out of reach of children. Follow the instructions carefully: install the battery first, then connect the UPS. Do not reverse the battery polarity, as this may damage the power management chip. Do not modify or add components. FAST CHARGING SUPPORT: Supports fast charging protocols with up to 18W output and 20W input. FUNCTION UPGRADES: Compatible with 4.2V, 4.35V, 4.4V, and 4.5V lithium batteries. Includes power supply side monitoring for current, voltage, and power. Note: Do not mix different battery types. Material: Plastic + Metal Color: Black Package Contents: 1 x Expansion Board Note: Light and display differences may cause slight color variations between the image and the actual item. Measurement error allowed within +/- 1-3cm.