Hello,
I recently played this hand and I really was not sure about the decision on the river.
What are we beating here?
For me looks like a fold what do you think? Looks like a very underbluffed line, and I am not sure if Ace with weak kicker would play like that.

PokerStars - $0.05 NL (6 max) - Holdem - 3 players
Hand converted by PokerTracker 4: http://www.pokertracker.com

Hero (BTN): 120 BB
SB: 116 BB
BB: 101.4 BB

SB posts SB 0.4 BB, BB posts BB 1 BB

Pre Flop: (pot: 1.4 BB) Hero has 6s Ad
Hero raises to 2.4 BB, SB calls 2 BB, BB calls 1.4 BB

Flop : (7.2 BB, 3 players) 5s Ac As
SB checks, BB checks, Hero bets 2.8 BB, fold, BB raises to 9 BB, Hero calls 6.2 BB

Turn : (25.2 BB, 2 players) Tc
BB bets 19.4 BB, Hero calls 19.4 BB

River : (64 BB, 2 players) 3s
BB bets 30.8 BB, ??