They work great. The pass-through makes it far easier to wire up and they have very helpful diagrams on the crimpers to follow rather than needing to look up a diagram.

I have a ton of Klein tools (the big back pack, wire strippers, screw drivers, etc.) so my expectations were high, but I was also confident in purchasing this tool.

Like any other Klein tool, the build quality is solid. It does everything from cutting, stripping, to the final crimp. You can pass through the wires as long as you need, pull it nice and snug, and it'll trim the wires down to the edge perfectly. The blades are very sharp and built to last. Did some practice crimps (in the photos) then proceeded to wire up my building with CAT 6 POE cables for my UniFi system (dream wall, APs, cameras, intercoms, the whole nine). Saved so much time and effort. Every single crimp came out perfectly and the connection was solid. Highly recommend. Will never do non-pass through crimps again!

Klein is know brand to always count on, it's dependable, durable and always one you can count on, I am a low voltage technician and this tool makes my job so much easier, easy to use, design, blade or cut off excess wire from the RJ45 is so helpful, recommend it to to any tech out there

I bought a different cheapo crimper on Amazon thinking that "how different could these things be, they all seem the same," but then I had to come back and buy these ones, because all of my cables had shorts in them with the cheapo crimpers. After getting these, I went back and looked at the teeth in the heads I had crimped with the cheapo crimpers, and they had been crimped to what I would say is the half way point between a fresh head and where these Klein Tools crimpers would crimp to. Even though these are more expensive than other options here on Amazon, save yourself some money and just get these ones first. I don't know if it is because these Klein Tools ones have a ratchet mechanism to crimp down harder or something, but it seems to just be doing the job right. I also seem to be able to put heads on cables faster than I can with the others for some reason, but maybe I am just more practiced. I actually only need to do the ratchet-crimp mechanism rather than strangling the wire after crimping down, so it probably does actually make it go faster. Stripping wire using these also seems to go faster than with the others.

Cuts sheath beautifully. Zero thought level.
Label for pin out is greatly appreciated although could be better printed.
Crimps hard.