4 AA batteries, embedded battery pack with lid but no switch

Product Name: 4 AA (No. 5) Embedded Square Battery Holder (with Lid and Switch)

Appearance and Structural Features:
Overall Structure: Black square battery holder, consisting of a "square mounting flange" and an "embedded battery compartment." The compartment is recessed into the flange, making it flush with the device panel after installation, for a clean and concealed look.
Material and Manufacturing: The outer shell is made of black engineering plastic (usually ABS) with a matte finish, resistant to wear and scratches. Multiple metal spring contacts are visible on the side of the compartment, used to secure the compartment and assist in electrical conductivity.

Functional Design (Key Features):
Removable Protective Lid: Equipped with a square cover plate with a snap-fit edge, the lid is stamped with "OPEN" and an opening direction indicator to prevent batteries from falling out due to vibration and to provide dust protection.
Integrated Toggle Switch: A miniature toggle switch is located on one side of the cover plate to control power on/off (some batches/models are labeled as "switchless" versions; please confirm this when purchasing).
Mounting Holes: Each corner of the flange has a countersunk screw hole for secure attachment to the device's base plate or panel.
Contact System: Four parallel slots inside the compartment, each labeled "1.5V AA/LR6/UM3." The negative terminal features a highly elastic nickel-plated coil spring, while the positive terminal uses metal spring contacts.

Dimension Specifications (Based on Image Labels):
Flange Dimensions: 92.7mm × 77.8mm
Compartment Dimensions: 65.7mm × 58.3mm
Total Height (h): 17.8mm
Weight per Unit: Approximately 34.4g
Electrical Characteristics: Internally designed as a series circuit, four AA batteries provide a 6V DC output.