It is the spark plug insulator. They are using the ceramic from it to break the glass. I remember hearing about this in the 90s with thieves carrying insulator

It is the spark plug insulator. They are using the ceramic from it to break the glass. I remember hearing about this in the 90s with thieves carrying insulators on strings in their pockets. https://www.carparts.com/blog/can-a-spark-plug-break-a-window/ https://www.carparts.com/blog/can-a-spark-plug-break-a-windo... note from the article: "Keeping Spark Plug Shards Might Be Illegal in Your State" so keep that in mind