You may have seen most of the symbols in other games of this type, including a young girl, some Chinese coins, a paper lantern, a drum, some scripts, a gold ingot, a red purse and some firecrackers.
This is triggered by landing at least one lion mask anywhere on two, three or four reels; the lion (or lion) will now expand to cover all positions on that reel and you will get a free Respin.