The Omron H3Y-4 AC24 10S is a socket-mount time delay relay from the H3Y series, switching up to 3A at 250VAC across four independent form-C contact sets. It operates on a 24VAC supply and covers a 0.5 to 10 second delay range, adjustable by hand dial. The timing mode can be set for either off-delay or on-delay, initiated by applying the input voltage.
The 4PDT (4 Form C) contact arrangement gives you four independent switchable circuits per relay, each rated 3A at 250VAC. That covers most pilot-duty and small-load switching inside a panel — signal lamps, contactor coils, solenoid valves — without needing a separate interposing relay per circuit.