To be a dead ringer means to be identical in every way.
1. The Sachin Tendulkar look-alike attracted a lot of attention amongst the spectators as he was a dead ringer to the real little master.
2. Mihir mistook Vidya for his old classmate Vijaya as her hairstyle and facial features made her a dead ringer to Vijaya.
3. Although Bharti and Bhavana were twins, nobody had problems in knowing who was who as they were not dead ringers.