Good product if you are doing networking. Would recommend.
PROS: I used this to light both SMF and 50 µm MMF links with no problems. I didn't expect the SMF to work but apparently the tolerances are good enough! Your mileage may vary though.
CONS: Will not work if you are doing digital audio links with optical S/PDIF (Toslink) connectors! I saw one reviewer who had done this. Almost did not buy the product because of it. But he mentioned his cables having rubber connectors, so I knew it had to have been the wrong application (SC cables don't have any rubber).
CONS: Optical cables do not fit inside far enough to "Snap" in. I had to cut off the rubber around the cable just to get it to fit and it still didn't fit correctly. I had a one above tv and one below tv to hide cable in wall. The connection is so bad that I got NONE, ZIP, ZERO sound into my receiver. I ended up using it as an extender for my 2 optical cables and it works fine for that, but that's not what this is intended to be.