The 5050 refers to the actual size of the LED package that is soldered to the circuit board. That size is 5.0 x 5.0 mm., so approximately a 1/4 in. square. If one of your choices does not give a 4 digit number in its description for size the only way to compare them is by light output which is lumens.
I have ordered several LED lights on eBay that are from China. All have worked and all are still working. I would prefer not to get LEDs from China, but the price difference drives me to do it.
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