Nice lights but very little change in intensity between tail light, brake light, and signal. My fear was it wouldn't be instantly noticed by following traffic. I liked the style and flat design so I simply added small marker lights I had to either side of the back of the trailer and wired them in to the brake and turn signals. Works great. Being flat I think these will be less exposed to damage as are the large incandescent style lights.

I have spent significant hours looking on eBay, Amazon, Banggood, and AliExpress for compact trailer lights that have a reduced size to limit the damage that all my trailer lights end up seeing. These are it!!!
They have an aluminum backing plate and the lens' plastic is tough polycarbonate rather than the more common fragile acrylic.
These are small enough to place almost anywhere so installs are easier and lend to locations that reduce the likelihood of collision and impact damage.
They look great too.

AT-HAIHAN DOT Compliant LED Waterproof Surface Mount Lighting:

Nice rugged lights with aluminum backing plate. Nicely made with clean finish and molding. Come with zinc plated mounting screws and nuts. Require two end mounting holes and a larger 1/2" center hole to feed wiring (easily achieved with inexpensive Harbor Freight step drill). All LEDs are illuminated in both tail and brake/turn modes.

The aluminum plate is likely an integral part of the design to dissipate the high heat from bright LED lights to extend life - these run cool.

The molded plastic lens is pretty thick and should take a fair hit without breaking. The lens shape makes the light visibly brighter from the rear but the lights are still quite visible angled off to the side. That said, these lack the dedicated 90 degree 'side' light' often found on trailer lights to alert passing vehicles that there is an unexpected trailer hanging out there. I would be sure add separate dedicated side lights to trailers if using these as the rear light assemblies. (BTW - these lights make great side lights as well.)

My only complaint would be that there is limited difference in intensity between the tail and braking/turn modes due to all LEDs being illuminated in both cases and the very bright tail light mode. Often LED tail lights leave 4 or so end LEDs unlit in tail mode and the remaining LEDs fed via a larger resistor to drop the voltage/intensity a bit; brake mode illuminates all LEDs via a smaller resistor to achieve a uniformly brighter light from all LEDs. The simplified design of this model works fine and is DOT approved but I have some expectation that the normal tow vehicle brake/turn lights may continue to play a role for brake/turn situations.

Recommended - with caveat for added side lights even for small trailers.

Used as head light on tractor

I have a small trailer that I pull with my motorcycle. Most cycles have turn signals on a circuit separate from the brake/taillight. I'm using this amber light for turn signals on the rear of my trailer, making a nice attention grabbing blinker by splicing the two wires together so the entire light flashes with my turn signal.