UScooters - GT Sport

the gts has a real brake, the others only have an electric one, which isnt bad but i wouldn't trust it to stop in an emergency

I have a uScooter GT Sport (aka, Fluid Mosquito). I don't know if it hits all your requirements, but it's close. It's 27 lbs, folds, is "UL Certified", and is "IP5X" rated. I put those things in quotes as I'm not sure how true it is. I've never confirmed the UL certification and from what I've heard, the IP5X rating isn't really all that true. For the screen at least. Water ingress seems to tend to kill the screens, preventing the scooter from turning on. The other issue is, I wouldn't want to ride the scooter at all when it's wet out. Solid tires do not work on anything other than dry pavement or hard packed dirt. It tends to slide all over the place when it's wet out. That being said, I absolutely love the scooter. I use it more than even my Nami Klima. It's ebrake is amazing, it has very low maintenance drum brakes (no oil), and at worst, a friction brake by slamming on the rear mudguard. The "pick up and go"-ness of the entire package makes it easy to just toss on a helmet and gloves and go out for an errand. Compared to my Klima which I feel like I need my full face helmet, better gloves, maybe some elbow and knee pads. Just a whole ordeal which I don't always feel like doing. I'd maybe suggest an EUC (electric unicycle) instead, but I don't think any are UL Certified. Quite a few are IP rated though. They're not super light, but they're easy enough to move around.