Triangle and Green Dot....What are they?

The green dot indicates "hospital grade", IIRC. Means tighter grip so your heart monitor won't come unplugged when you roll over ;~)

Not sure on the triangle, but the green dot indicates that the outlet is certified as "hospital grade", meaning that it is safe for use in areas where flammable gases are in use.

The triangle indicates that the device is an isolated ground receptacle.

The orange triangle indicates that the receptacle is an isolated ground receptacle. The ground contacts in these receptacles are, by design, isolated from the mounting yoke. This allows you to separate your equipment ground from the ground for the box and the conduit (and the face plate if metallic).

Thank you.

I have an Audio Magic Stealth Digital Mini, and the left socket has the green dot & red outlined triangle.

Thank you all.