Verizon Vzw6400Silbb-Oem Verizon Double Cover Case For Htc Thunderbolt 6400 (Black / Blue) OEM Verizon Double Cover Case for HTC Thunderbolt 6400 (Black / Blue) Two layers of protection provide bump and scratch protection. Protect your phone with a plastic snap-on cover and a thin inner layer of silicone. Cover is specially designed to allow convenient easy access to device keys, ports and device features while in cover.