What video resolutions does this HDMI 2.1 cable support?

This cable supports video resolutions up to 8K (UHD), 1440p (QHD), and 1080p (HD).

What is the diameter of the Cablecc HDMI 2.1 Ultra Thin HDTV Cable?

The diameter of the cable is 4.0mm.

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Cablecc HDMI 2.1 Ultra Thin HDTV Cable 8K 4K Hyper Super Flexible Slim Cord Left Angled to Right Angled 90 Degree Type-A for Computer HDTV

HDMI 2.1 Ultra Thin HDTV Cable 8K 4K Hyper Super Flexible Slim Cord Angled 90 Degree Type-A Male to Male for Computer HDTV
The angled type Allowing you to connect it to a female port, even if space around the port is limited.
ULTRA THIN CABLE:
The ultra-thin and flexible high speed cable with 4.0mm diameter fits perfectly in tight spaces, designed for gimbal, camera stabilizer, and rigs applications where flexibility and compact cable routing is required.
HIGH SPEED: Industry standard 48Gbs bandwidth allows for unrestricted video in 8K (UHD) 1440p (QHD) and 1080p (HD). Enjoy unparalleled video quality, crisp and accurate sound, and buffer-free ethernet connection with these HDMI cables.
GOLD PLATED CONNECTOR: High quality gold plated connectors ensure a solid connection with all your devices. The welded design and heavy cable ends guarantee longevity and ensure your cable doesn't break from being accidentally tugged or pulled on.