Energy Knight's Type Rail Cover Set (2/4/5/6 Ribs x 2) Black
[AS3469]

Cheap but effective.

they look great on a rifle, and they do what they need to.

As stated in other reviews, fitting them onto the rails takes a little effort, but I managed to get all of mine on.

Some of mine don't lock into position, but they fit tight enough that they don't slide around without considerable force applied.

For the price, it's worth it, but if you for some reason want "perfect" covers, or perhaps you suffer from severe OCD, then you may want to look at some better quality covers.