Molex Micro-Fit 3.0 dual row (4 Circuits) Male & Female receptacle plug, w/Terminal sockets, (Pack of 5 Set)

No problems with the product itself. The pins are so small they're difficult to work with without a specialized tool, but I feel like there were plenty of pins for my needs. I needed this to make an extension cable for my Vevor diesel heater controller and it was the exact size I needed. I took a gamble and it paid off. I will just say, however, that there are actually only 3 wires needed for it and these connectors allow for up to 4 wires, so if you're using it for you diesel heater or something else be careful to wire up the pins/connectors correctly so it aligns with the stock male/female connectors in the diesel heater or other device(s) you're connecting them to. That should go without saying, but I figured I'd mention it just in case someone hadn't already considered that themselves.

I bought these to make an extension of the wire for my Bambulabs AMS Lite. They worked fine.

Not many choices

I ordered these to make inexpensive 4-wire test cables for use with resistive temperature detectors, and I chose 24 AWG cables for good flexibility. I had some trouble with other connectors that were listed as suitable for 24 AWG wire, and I can usually get good results with crimped connectors, even if I'm not an expert. I chose these Micro-Fit connectors because they're a little smaller but still fine for my low-current application, and I immediately got good and consistent results. My first crimps were good, all 8 of 8, enough to complete two connectors so I could test them. The connections seemed mechanically sound and the wires felt firmly crimped in place. Electrically, the two mated connectors added roughly 4 milliOhms to the resistance of each circuit, and they all measured within 1 milliOhm of each other, which I found reassuring. These initial sample results are well within the Micro-Fit connector specs that I've found online and are certainly good enough for my purposes, so I'm comfortable thinking they will be quite robust.

Needed a few of these for a 3d printer i was wiring up, i could have bought from somewhere like digikey or mouser. But these were cheaper overall when you factor prime shipping. I bought a microfit kit from elsewhere but it didn't have 4pin 2x2 so ended up grabbing these. They were genuine and same as the ones that came in my kit quality wise. You'll need some crimpers with these. I used IWISS IWS-2820M AWG 28-20 crimpers (B078WNZ9FW) and all went well.