The parts of apparel mockup kits like American Football Kit Mockup or Men’s Full Soccer Goalkeeper Kit are usually not meant to be separated or removed, they are created to be used as fully equipped sets on purpose. Having said that, some mockups actually do have an option to be altered by removing some layers. If that's the case, you will see it in the description of the object.
We offer a huge variety of Object Mockups, there are more than 30,000 mockups in our collection currently, and it's growing day by day. So we encourage you to search for suitable items at our stocks.