The use of this mini-torch is very easy:
Screw cap at the rear end, the insert in the blister packaging supplied AAA battery, screw cap - ready for use. Switched on is the same by turning the head end.
About turning of the head switch and the light beam of point radiation is switched to room radiation.
The lamp is lit with its 37 lumens really very bright, but there are some comparable competitors with significantly more luminance, so for example. The even smaller Kraftmax X100 or also the Olight I3S EOS, with their respective 80 lumens actually the night day will be - both models also cost little more than the MAG-LITE SJ3A016L.
The MAG-LITE is to IPX-4 standard splash-protected, the others are even waterproof to IPX-8 up to 2m deep.
Conclusion:
The lamp is lightweight, which is no additional burden on the keychain.
As a "last resort", the brightness of this flashlight is always sufficient and the burn time is long enough.
But there is in dimensions and price comparable "Hand work lights" with more features.