One of the preschool math standards in Massachusetts is using non standard units of measurement.

There are a wide range or materials you can use as non standard units of measurement from shoes to toy cars and more. 

In my experiences, one of the most fun is using links to measure long distances such as the length of a classroom, the length, of a playground, or the length of a hallway. The long distance seems to get children more engaged than measuring short distances. This can be paired with another preschool math standards related to estimating and counting. Before measuring, you can have all the children estimate how many links a certain distance will be. After completing the measurement, you can go back and compare that to what was estimated. Keep a record of both the estimated guesses and the results because you can review them later before you try to measure a different distance.

To make it a long term project, during an activity time you can have children begin attaching links together in preparation for the measurement. This builds fine motor skills and allows children to work as a team. For an extra challenge, you can ask children to create color patterns while connecting the links.

Children working together to build and hold the chain links helps children learn team work as well.