Mr. Theobald supplied me with the materials, guidance and answers to any questions I had concerning my preparation for the CPO exam, after which I took & passed in North Charleston, SC. He is extraordinarily qualified, exceedingly knowledgeable and also very professional in this field. Thanks to Mr. Theobald I have advanced in my job after receiving my South Carolina public pool operator certification (CPO). Thanks again to Daniel L. Theobald.