I emailed a lady at tmobiletowers.com to see who just added panels on the site. She said she checked with the legal department and that information is proprietary. That said, it's 4 cellular white panels. Verizon's been using those panels, but often with 1-2 PCS panels. It's most likely Cingular, who also uses the same panels as Verizon, but doesn't use PCS panels. That said, I haven't seen an improvement in coverage yet, but they're only 2 weeks old at the most. Nextel gives out the information readily, and even tells who about who is thinking of adding to the site! I wonder if that will all change with the Sprint merger.