This is a high quality and accurate digital caliper at a very good price. It takes on both internal and external dimensions. The caliper comes in a hard plastic storage box that provides a secure fit. It comes with one battery installed and one extra battery in one case. The battery is easy to swap out, no screwdriver required - there's a plastic tab that just pops open. It also comes with a pen with 32 different thickness blades stamped with both inch and metric sizes. I used a caliper to measure the sensors and everything was fine so I'm not worried about the accuracy. In my photo I'm measuring a .0350" dipstick and the gauge says exactly that. The dipstick blades are lubricated and quite oily. So keep that in mind before you use it and stick it on your fingers Good storage solution so I'd say it's worth the money.