I realized with a moving bed it basically pumps air though it and increases the delta in temp from the center to the edges. I could have ordered stick on bed isolation but that's no fun.

The part clips on and will tighten up snug to the bed when it gets warm and everything expands. Hold temps with about a 3 degree delta and much smaller temp swings of about 2 degrees.

I printed them at a 45 degree angel to fit on the bed

*I have the PowerSpec branded version of the Duplicator i3 Plus

I realized the bed warped right away on the Duplicator i3 Plus and the edges weren't sticking. Found that years ago with my old Replicator Dual (MakerBot Clone) if i had it in a cold room the heated bed would cause the bed to warp because the center was much warmer (expanded) than the edges (cooler wanting to hold its size) on top of increasing the delta from the center to the edges.

On the i3 Plus with a infrared thermometer i saw there was a 5 degree delta from the center to the end of the heating element (about 15mm from the edge), After I let the bed sit for a few minutes to make sure everything equalized, and when printing the bed moving though the air made it worse. The edges had a 5+ degree temperature swing and the center ran warmer, with probably a 7+ degree delta at times. Pretty bad

The skirts are to stop air from moving under the bed to keep the bed from cooling and more evenly warm the bed. Not the best solution, but will help. A proper stick on insulation mat for $5-$10 USD off eBay should work better, but you can always use both