U138 by M5Stack is a ethernet development tools designed for reliable performance in electronic applications. It is widely used in industrial, automotive, and power management systems.

Development board, kit, and programmer products include tools and assemblies used for product development and evaluation purposes. Evaluation boards are produced by a manufacturer to allow prospective users a convenient way to characterize device behavior in context of a known-good implementation, whereas development boards and kits typically include additional features or accessories intended to aid a user in developing their own product based on some device. Programmers and related products are used for configuring products having a behavior that is user-adjustable or user-specified, such as a programmable oscillator or microcontroller.