First off, these make daisy chaining LED landscape lighting very simple. I would like to thank the gentleman who posted the video on using a pair of channel lock pliers to push the low voltage cable down onto the piercing teeth for good and snug contact. However, I am only giving four stars because I cannot see how this is waterproof and how water will not get into these. I used 14G wire, and had to use the 12G slot, so there is the gaps around the wires from that. Secondly, there isn't a rubber gasket that seals these together. It is just screwing the two sides of plastic together. We will see how this holds up to rain and snow over the years. I ended up taking a bunch of electrical tape and wrapping these all up to try to keep as much water from seeping in as possible.

These provide a connection between lv light/fixture and lv cable that is SO much better than the clip that comes with the fixture. I've never had to reconnect one of these. Recommend!

The lamp base in the light fixture got messed up - one of the contacts somehow got pushed down and didn't connect. I fixed that easily but at the cost of messing up the connecting device to the 12 VDC feed 'lamp' cord.
I messed around with THAT for about 45 minutes before realizing a 'fix' might work but the likelihood of continuing to work was approximately about the same as an apple sinking in a bucket of applesauce. So ,,,, off to the Amazonians to quickly find this set of two connectors. Then after a 'Prime' wait - one day - time for installation. And first time success. Wonderful connector that was EXACTLY suited for the job!

One other note .... I fastened the connector to the top fence 2 X 4 after installation by removing one of the closing screws at a time and replacing each with fine gauge screws that were 5/8" longer and had same width heads. This move just to assure wind could not jimmy up the electrical connections inside.

I used them to branch landscape lighting off of the main line

The idea is that you have multiple lights with 18 AWG zip wire that you need to attach to a powered 16 or 12 AWG zip-wire line without cutting the line. There is a separate pass-through slot for 16 and for 12, BUT NOTE that some 16 wire is too thick due to insulation for the 16 slot. It worked for me to just use the 12 slot. The connector comes with both slots sealed with rubber. You remove the rubber from the slot you want to use. The 18 AWG does not pass through: it comes in through one side and stops inside.

You might expect that tightening the sides together with the screws would supply sufficient pressure to ensure piercing to get electrical contact. THAT IS INCORRECT. You will need to use pliers to squeeze the wires down onto the piercing points. Read my instructions below to avoid frustration!

If you had a live 16 AWG line, you would remove the three screws, separate the pieces, and proceed as follows:
(1) Remove the rubber plug from the 16 slot. If your 16 AWG wire is too thick, use the 12 slot.
(2) Lay your 16 AWG wire so that it is centered in the slot over the two piercing copper points.
(3) Press down on the 16 wire with your thumb to start the piercing and help secure the wire. Then use slip-joint pliers to squeeze the wire against the copper point. NOT DOING THIS COULD LEAVE YOU WRITING A BAD REVIEW LIKE THOSE THAT SAY THE CONNECTORS DON'T WORK!
(4) Lay your 18 AWG wire centered in its slot. Do not separate the two parts of the wire. If they are already separated at the end, cut off the end.
(5) Squeeze the 18 wire and the 16 wire with pliers again and then put the cap on them and tighten the screws.

The connector shouldn't be bothered by moisture or rain; however, I would not want it submerged because the seal around the zip wire and the edges would probably not stop seepage. If you have a risk of submerging, I'd put some silicone sealant around the edges of the plastic pieces.

I gave the connector 5 stars because it is very well designed and works reliably for me.