FOR EXPERIENCED USERS. IF YOU ARE HAVE TROUBLE SETTING IT UP PLEASE CALL FREE TECHNICAL SUPPORT AT 1(800)521-THOR (8467) Ext 2 (MONDAY-FRIDAY) This is 2 PACK of a very popular H-HDMI-RF-PETIT Digital CATV HDMI modulator. The 2 modulators can be combined by cascading from one output to another output or external 1x3 RF combiner (not included). The most unique and cost-effective Networked Digital HDMI RF modulator. Designed to allow any HDMI source like an STB, satellite receiver, HDMI camera, DVD player, Computer, and a ROKU device. You can convert to any RF TV channel of your choice. This Thor Modulator is an all-in-one device integrating HD MPEG2 encoding with AC3 Dolby Audio with an internal digital modulator. Converts HD audio/video signals from any device into DVB-C/T/ATSC/ISDB-T RF output. The unit supports any HD source with the following video resolutions: 720p, 1080i, 1080p Simply connect to any PC and control the unit via Thor Broadcast's proprietary GUI which has been touted as being the best on the market. This unit is plug and play and has exceptional quality for a very low price to help anyone with any budget create their very own RF channel which can be viewed on thousands of televisions simultaneously. This item comes with 2 petit modulators.