Enhanced handguards and rail kits can be quite expensive, especially if you don't need all of the features. Sometimes all you want is to add a vertical grip or torch etc, and shelling out for a high end rail kit is a little extreme.
Thankfully you don't have to! This RIS/RAS rail has been specially designed for use with the M4 carbine handguard - they simply bolt in place onto the top and bottom of the plastic handguard. Installation is quick and painless, requiring only basic tools.