Most flexible pipe insulation

I have some pex lines that curve from the manifold up to where they go through the floor to their respective heating loops. What insulation (to block light - heat is secondary) would likely be the most flexible and stay closed around the pipe while following the curves?

Armor-flex

insulation

There is split foam insulation for use when the pipes are already installed. You snap it around the pipe, then pull a plastic strip off both sides of the joint and press it together. The contact cement on the edges bonds together to keep it sealed, so do not remove the strips until you have it in place.

I've previously insulated all the pipes I could get to but didn't do that to the pex hydronic circuits since I didn't mind heat being added where they ran. Since some of those can see some indirect daylight, I need to do them, too. Don't really need the insulation except for the UV. Based on what I've read, I could also paint them. Thought it would be cleaner to insulate and needed something flexible to fit the curves without the seam coming open. Am looking for brand recommendations. Might be easier to just paint them, though.

Uv

Indirect sunlight does not have UV