Heavy flavor leptons provide an extra handle on the open heavy flavor mesons, since they come from semi-leptonic decays of D and B mesons with significant branching ratios. Once produced, leptons do not participate in the strong interaction in the later stages of the collision, and remain a clean probe into the whole evolution of the system. Apart from TPC and TOF, BEMC is used to improve electron identification, and MTD is used for muon detection.