Dual SIM phones indicates that one cell phone with two SIM card slots,and you can receive two calls simultaneously(namely dual standby).People are always pesky in taking two cell phones when on business trip.Now,dual SIM phones have solved this issue,you don't have to take two cell phones beside you,unnecessary to switch between two sim cards,it is rather easy and convenient for you to receive two calls from two different countries at one time,that saves your much time and energy,more importantly,your peer never get message "Sorry,you dialed number is busy now,please try later" and get you through instantly.