$500 eff. I open A♠ K♠ UTG+1 to $15, MP1 calls, BB calls.

Flop: K♥ K♦ 4♥ $47 BB checks, I bet $30, MP1 raises to $85, BB check raises to $200

Reads: BB is a nit and never has a flush draw or a bluff. MP1 is loose preflop but tightish and passive postflop and he also never has a flush draw or a bluff.