1具有显示24秒计时功能；
2设置外部操作开关，控制计数器的直接清零，启动和暂停/连续功能；
3计时器为24秒递减计时，计时间隔为1秒；
计时器递减计时到零时，数码显示器不能灭灯，同时发出报警信号(1 has the function of displaying 24 seconds.
2 the external operation switch is set up to control the direct zero, start and suspend / continuous function of the counter.
The 3 timer is timed by 24 seconds, and the time interval is one second.
Timer timing decreasing to zero, the digital display can not be off, and send out alarm signals)