This is the original - WSPRlite, now known as the Classic. The WSPRlite Flexi is a different model that added higher HF bands and extra features.WSPRlite is a special, low-power test transmitter that sends a signal on your antenna out to a worldwide network of receiving stations listening in the WSPR mode. When used with the web-based DXplorer system, it's a powerful new way to evaluate antenna performance. This unique system of propagated signal analysis goes beyond antenna modeling or antenna analyzers. WSPRlite and DXplorer allow you to see how your antenna is performing in its actual location and in real-time! Imagine the possibilities! You have never seen signal and antenna analysis like this before: - Antenna performance testing (great for contesters)- Compare any antennas – base, portable and mobile - Compare locations and antennas - yours, your friends, even compare your antennas and location with the big guns - Test beam antennas against dipoles versus verticals - Spot openings when you are out of the shack (great for DXers)What makes this product unique is the ability to compare the performance of antennas and locations. WSPRlite is a self-contained propagation beacon transmitter. Once configured using a special Windows app (third party LINUX and Mac support available at WSPRlite Facebook Group), WSPRlite only needs a USB power supply to operate (no need to tie up your computer). WSPRlite is capable of operating 630, 160, 80, 40, 30 and 20 meters, and is supplied functional on 30 and 20 meters. Operation on other bands requires a band-specific low pass filter kit. This Low Pass Filter Kit that you can build for 160, 80 or 40 meter operation is also available here. SOTAbeams does not make an enclosure for the Low Pass Filter at this time. WSPRlite has accurate digital power control over a 16 dB range to facilitate precise measurements of antenna performance differences. Although the WSPRlite operates at only 200 mW, clever encoding of the WSPR signal gives it the DX capability of a high-power transmitter.The DXplorer software and website is specifically designed to operate with WSPRlite. DXplorer provides you with antenna performance information and propagation information in a new easy-to-use format. DXplorer has even been optimized for use on mobile devices. When you set up your WSPRlite you receive a unique link that provides 1 year of free access to DXplorer Premium, a $20.00 value. Enjoy additional testing and reporting facilities, including detailed antenna comparisons, as soon as you get started!Join the next generation of antenna and signal analysis with your SOTAbeams WSPRlite Propagation and Antenna Tester from the exclusive distributor in North America, DX Engineering.