Smoke detectors okay, battery weakness

Have us these smoke detectors risen because they are in BW since 01.01.2015 duty.
Smoke detectors are made of high quality plastic, even survived a fall from the ceiling to the floor.
The only weak point is probably the supplied batteries China, the case of a smoke detector honked once, so switch battery and behold works.
The smoke is really noisy, can hear you him not. In the middle of the smoke detector a small light-emitting diode is mounted the flashing about every 5 minutes.

In short smoke detectors okay, only the China batteries are probably the weak point