The features of a 4 group lab timer may include:

1. Independent Timers: Each channel can be set with a different time duration and started or stopped separately.
2. Countdown and Count-up Modes: Most timers allow you to either count down from a preset time or count up to monitor elapsed time.
3. Audible Alarms: You can set alarms for each channel to notify you when the time is up.
4. Digital Display: Clear digital displays show the remaining time for each timer.
5. Memory Function: Some timers may have a memory function to recall previous timer settings.
6. Battery or Plug-In: They can be powered by batteries or plugged into an electrical outlet, depending on the model.

These lab timers are essential tools in laboratories where precise timing and coordination of multiple experiments are required. They help ensure experiments are conducted with accuracy and safety.