I bought these for a customizable free float tube I was building. It not only worked well for that, but I also found that they would mount fairly well to most AR15 handguards. The only minor complaints I have are:
1. The rails are slightly too wide, so you have to push pretty hard to get some accessories on there.
2. The mounting screws are fairly worthless by themselves. Not a big deal, as I just used other screws and brackets that I had on hand.
Overall, I am very happy, and I would buy them again.
Pros: Inexpensive, decent quality, works for some AR15 handguards
Cons: very slightly too wide, mounting screws are very limited in use
This review was written in the old system and had content requirements that are different than reviews written today.