This is just a hard drive drive. if you want to use it as external, you will need an external adapter.. or IDE enclosure. An older external disc drive enclosure would work as well.
3.5 is for desktop. Laptop is 2.5,,I do have a 60gb for IDE laptop Ill be listing soon. But you will need to know if your laptop is IDE or SATA. I dont have any 2.5 SATA hard drives at this time.