Skilled technicians use reflection boards or LED lights during PDR to read the dent shape precisely

https://martinhwtj700.ironwoodscope.com/posts/auto-body-dent-repair-vs-paintless-dent-removal-what-s-the-difference-2

Skilled technicians use reflection boards or LED lights during PDR to read the dent shape precisely and apply controlled pressure exactly where the metal needs correction.