GDTP Certification Prep Course The GDTP Certificatoin Prep Course that I took from Applied Geometrics Incorporated greatly prepared me for the Senior Level Exam. The course identified what areas I needed to work on, the approach that I needed to take and what to expect when taking the exam. Not only did I just pass the test, but I passed with flying colors. If anyone is really serious about taking the Senior Level GDT Certification exam, I would higly recommend taking this course from Applied Geometrics Incorporated to greatly increase your chances in passing the exam. - Rob Heller