One of the 2 pieces is defective - the small section of the channel was too small, so the BNC plug fitted, but is not blocked. So I'm sending them back and ordering a new set. I hope to get 2 good/useful ones from this purchase/return/reorder. I'm sure they make 10 batches out of 1000 and maybe I just got a bad one.
4K / 30Hz USB-C to HDMI Adapter - 3-in-1 Type-C Converter Cable for MacBook Pro, MacBook, Mac Pro, iMac, Chromebook, and USB 3.0 Type-C Devices (2017/2018)
13 Review
Cable Matters USB C to HDMI Adapter - 4K 60Hz, 60W Charging, Thunderbolt 4 Compatible for MacBook Pro, iPad Pro
12 Review
Tobenone USB C to USB Adapter with π» 2 Ports for MacBook, Dell XPS & More Type-C Devices
13 Review
π΄ 2 Pack JSAUX HDMI Coupler Female to Female for 4K HDR Extension - Aluminum Alloy Adapter for HDTV, Roku Stick, Computer, Monitor, Laptop, Projector, DVD Player, PS 4/3 (Red)
12 Review