These lamps have two different styles of layout in the first the loops or tubes are aranged in a triangle and in the second they are in a row.

The reason for this is they give different spread of light the picture on the left is the triagle and the one right is the straight loop.

The wattages are not interchangable you cannot fit the wrong lamp in the lamp holder.

Again colour tone is important.

downlighter tubes PL ecotone U tubes triple turn