The HTC ThunderBolt (ADR6400L) was the first 4G LTE smartphone on the Verizon Wireless network. It is a CDMA/LTE variant of the HTC Desire HD. It was first announced at CES on January 6, 2011.

In telecommunications, long-term evolution (LTE) is a standard for wireless broadband communication for mobile devices and data terminals, based on the GSM/EDGE and UMTS/HSPA standards. It improves on those standards' capacity and speed by using a different radio interface and core network improvements. LTE is the upgrade path for carriers with both GSM/UMTS networks and CDMA2000 networks. Because LTE frequencies and bands differ from country to country, only multi-band phones can use LTE in all countries where it is supported.