The 4th gen Aurora A3 has a USB-C port, metal switch, magnetic two-way clip, and a better user interface, etc. All these upgrades are based on the fact that the size keeps the same. It's still in a small keychain size with a powerful output.

Its length is 57.5mm and diameter is 15.6mm, weighs only 23.1g.

The upgraded metal switch gets clicking more comfortable and strong feedback. Regarding the user interface, it has a lockout mode and keeps the momentary-on feature. 

The Aurora A3Pro torch light is made of 7075 aluminum alloy, which is usually used for transportation and aircraft due to its excellent mechanical properties, and exhibits good ductility, high strength, toughness, and good resistance to fatigue; with the hard anodization (Desert Tan), it has good scratch resistance as well. 

OPERATION OF NEW A3 PRO G4

Press and hold : OFF → Momentary On(High), release= Turn Off.
Long Press 0.3s : ON →Turn Off.
Single click : ON → Cycle thru Moonlight-Low-Med-High.
Double click : OFF → Constantly on from memorized mode(Moonlight/Low/Med/High).
Triple click : Strobe
Quick 5 click : Lock ←→Unlock (Charging can instantly unlock)

Note:

When the light is working at High/Medium mode more than 1 minute, it will gradually step down to 80 lumens to protect the light bulb and the user due to the massive heat generated.