What wavelengths should a red light therapy panel have?

Across reviewers, the standard pairing is 660nm red (surface/skin) and 850nm near-infrared (deeper tissue). Specialist red-light subreddit threads we read note that 810nm and 830nm are actually preferred over 850nm for deep penetration, but 850nm is the most commonly available and is generally considered acceptable. Higher-end panels add 630nm, 810nm, or 1060nm for broader coverage.