We upgraded our iMacs to 2019 models and no longer had an HDMI port for a second monitor. We ordered a (much) cheaper adapter here and it didn't work. We spoke to Apple for 90 minutes and then ordered. Turns out we didn't check the Hz on the monitor. It was 60 Hz, which is what this adapter is designed for. Less expensive adapters are designed for 30 Hz. It's perfect, it worked right away.
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)
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USB to USB Type-C adapter
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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)
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Cable Baseus Cafule USB - Lightning, 1 m, black/red
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