Which of the following is an example of a manual irrigation device?

A quick coupling is a manual irrigation device because it provides a simple and immediate way for users to access water for irrigation purposes without relying on automated systems. Quick couplings are typically used in landscape irrigation for connecting hoses or portable sprinklers to the main water supply. They allow gardeners and landscapers to manually operate the irrigation system, enabling them to control the timing and distribution of water as needed.

In contrast, other options represent devices that automate or schedule irrigation processes. A sprinkler timer and a smart irrigation controller are designed to automatically manage watering schedules and adjust for environmental factors or soil moisture levels. An automatic valve, on the other hand, operates without manual intervention, opening or closing based on signals from irrigation controllers. This automation is beneficial for efficiency but does not fall into the category of manual devices. Thus, the quick coupling stands out as the only option that requires active, manual participation in the irrigation process.