i have tried the drills that have batteries in the body of the drill [SEP] and while they do not seem to be bad they just do not have the power that this one does i am thinking it has to do with the size strength of the battery in the drills attached power supply while i do use this for my fingernails i am using it more for my toenails and feet toenails are thick and tough and i have trouble cutting them well even with good toenail clippers so being able to file them a little at a time is much easier also i have some very hard thick skin on my feet and grinding that skin down is much easier that using a foot file this is a wonderful nail drill that is not just for nails sturdy like a workhorse it will make short work of messy nails or hard callused skin