Just go for it.
My trailer had regular 18W wedge bulbs (T9 socket). After much procrastinating went to Ebay and got it.
24 5050 SMDBrightness - identical to old ones.
Color - identical.
Amps - 5 times less (0.3A per bulb VS 1.5A of the old ones).
Installation - what installation? Pull out old bulb and plug this one in.
No photos, but trust me, they are really identical to old bulbs in color and brightness.
Also got smaller 12 5050 SMD for kitchen hood - didn't fit well, the cutout in the hood is fraction of inch smaller than that LED disc. No big deal, I plugged it in, laying loose inside of the lamp cover.
You do want 300 lumen brightness and "Warm White" color temperature if the goal is an exact equivalent of an old 18W bulb. There are LEDs with higher and lower lumens and whiter-bluer color out there.
My reason for procrastinating was - I'm a light user, under 40 AH a day. Batteries are full every day on solar, cycling from 90% in the morning, 95% Absorb at noon and 100% Full by sunset. Don't even know why I needed LED, just did what everybody did. Maybe will need it later in short winter days.
Here is a catch - now I'm spoiled and find that an exact equivalent of an old 18W bulb is dim and yellowish (just like the original 18W was), and want more brightness and white-ness.
Also - want more diffused light. Bulbs few inches above my head with stupid clear lens in the middle of frosted dome cover make for sharp shadows. Nothing beats a shore cabin with normal light fixtures, tall ceilings and 110V grid.