3AA battery pack with lid, switch, and USB plug

Product Name: 3 AA (Size 5) Battery Holder with USB Power Supply (Covered, Switched, with USB Plug)

Appearance and Structural Features:
Overall Structure: This is a standard black rectangular battery holder designed specifically to hold three AA (Size 5) batteries. It features a classic series connection layout, with a square shape and rounded corners.
Material and Manufacturing: The outer shell is made of black engineering plastic (usually ABS), with a matte finish, making it sturdy and durable. The side of the box has sliding rails that work with the latches on the cover to ensure a tight seal.

Functional Design (Key Features):
USB Output Port: This is the most prominent feature of the product. A standard USB female connector is attached to the end of the wire coming out from the back. This means it can be used as a mobile power adapter to directly power any device with a USB male connector, such as small fans, LED strips, development boards, etc.
Integrated Toggle Switch: A miniature toggle switch is integrated on the circuit near the USB port or on the side of the box (depending on the version; in the picture, it's shown near the base of the wire) to control the power on/off, making it convenient to turn off the power without unplugging the USB device.
Sliding Lid Design: The top of the battery compartment has a sliding lid with the words "OPEN" and an arrow indicating the opening direction. This design makes it easy for users to quickly replace batteries.
Mounting Hole: The surface of the box has a round screw mounting hole for easy installation of the battery holder inside a device or on a panel.

Contact System:
Negative Terminal: One end inside has a highly elastic nickel-plated coil spring to ensure tight battery contact.
Positive Terminal: The other end has a metal spring contact.

Dimension Specifications (Based on Image Labels):
Length: 70mm
Width: 49mm
Height: 19mm

Electrical Characteristics: The internal circuit is designed as a series connection, and three AA batteries can provide a DC voltage of 4.5V. Since the standard USB voltage is usually 5V, the 4.5V output from this battery holder can directly power most 5V USB devices that don't have strict voltage requirements, such as LEDs and small motors, or it can be boosted to 5V using a boost module (if included).