5Pcs Black Waterproof Plastic Electric Project Case Junction Box 3.94 x 2.36 x 0.98 inches(100x60x25mm).

... but smaller than expected. I am enclosing an arduino uno and some extra light circuitry and a video box it too big (my usual project box now that I have so many surplus) so I found this good deal but can't use it. Still I will put them in my electronics supplies bin for sometime but not this time.

EDIT: big 2 star up grade! These fit 3,18650s perfect and there is room for a small 3p BMS. Also there is set of stand offs for a PCB as well..Shinny plastic box.. Not the dull solid ones I am used to. Fells flimsy compared to others. But the price is cheaper and it is a bit bigger then the normal ones as well.. Not going to stomp on it so.. It will work..

These boxes are small and cheap, but they aren't waterproof, unless you load up the seam with RTV. This is because the cover and the box itself aren't "perfectly mated to one another" due to manufacturing tolerances, and all they do is snap together.

I used one to mount a DIY 5V 12V Inching/Self-locking Wifi Switch Module ($15) next to the button for the electric garage door using Velcro. The lid fit tight. I cut a small hole for the power and to run jumper wired to the garage door button. Viola, inexpensive smart garage door opener. This project box has been functioning great since I bought it a year and a half ago. I would again if I need another project box.

Put a step down buck converter and Arduino Nano in this as an LED strip driver box. It's driving 2x 15ft strips for a total of 270 LED's. Drilled a hole for the power and USB in and LED out wires. It arrived in a larged padded envelope. I didn't receive any damaged units like the other reviewer. I suppose that's just the luck of the draw when it comes to being damaged during shipping in an envelope. Lid snap fit style, very well made snaps together no problem and flush, functions as intended. Perfect for my needs, very happy with it. :)

Lids do not seal to the bottoms other than with flimsy plastic indents. No way to secure them on other than gluing them. Lots of plastic flashing left on the parts from the injection molding.

I give them a five star rate, just the right size for many of the projects I work on, just the right price for the wallet. The plastic is a little on the thin size, but considering the price, they are very OK. I doubt that I would trust them as "waterproof" since there is no rubber gasket and no clamping mechanism, but I do believe they are at least water "Resistant." They do snap together with a nice click...and that's all I usually need.

I've used these boxes for my last dozen esp8266 projects, and just bought some more. They're a perfect size, and the quality is good. I'm not sure how other reviewers ended up with broken boxes; my last order also had 10 pounds of diatomaceous earth in the shipping box, and they came in intact. In fact, the boxes are somewhat flexible and well packaged together, so you'd have to drive over them with the car to break them. They're easy to work with a nibbler or drill bit. Love them!