As others said flip it over. I had to bend the wires a bit to insure contact.
I'll have to go back through my thread ans see if any of the other sellers of the units I use still have them. They are the 48 1210 panels and seem to be pretty popular. I did pick up one of the 10 for $17.99 packs and the only complaint is that they are a little too warm in color.
What kind of fixtures do you have? I find there is a difference in opinion in what works depending on which you have. The amount of light needed, cob or panel and even how well the panel stays up.
My fixtures are clear with curved metal reflector. The panel sticks to it well and illuminates under it very well but the spread is limited. A cob gives better over all lighting and a small lens in the cover directs some more othe light down but not like the panel.
Getting the panels to stick can be a issue but not for me. I cleaned the reflector with denatured alcohol and they stick so well that removing one without damaging the panel took quite a bit of effort. Cobs pop in and out like the regular bulbs.
Luckily we waited to install most of the LEDs while we were camping. The bright panel is great where we need it very well illuminated but they are over bearing in the ceiling fixtures. We use 9 1210 cobs on both sides of the four ceiling fixtures. They light the whole trailer nicely with less power than two of the panels.
Have a frosted lens, ask tenbear. :)