It's scientific calculator.From engeneering students to Bsc.Msc. basically Science field students as well Commerce field can use it for calculation propose. I bought this calculator from stationary for about 700Rs. It's working and have cell or battery in it.I used this calculator very lightly as I was life science students.Its better to consider it as new calculator. on its back side in right upper corner their is rectangle shape that from where you can remove or put cell inside it. But right now it's working properly so no need to put new cell.it will work without any problem for 2to 3 years.