4 way measurement refers to the way a caliper can accurately complete 4 types of measurements with just one tool. With a standard vernier caliper, you are able to take a 4 way measurement with ease and precision. The bottom jaws, located at one end of the caliper allow for outside measurements. To complete this part of the 4 way measurement, simply place the item you intend to measure within the two bottom jaws, adjust them until they are snug, and look at the readout. The top jaws, located directly above the bottom jaws allow you to take inside measurements. To complete this part of the 4 way measurement, put the top jaws within the space you are planning to measure and adjust them until they are in contact with the outer edges. There is a depth rod that extends from the end of the caliper. This can be used to make a range of depth measurements. Finally, the final part of the 4 way measurement ability of the vernier caliper is the step measurement, which is an alternative way to measure depth or height.