There are two kinds of VTAC modular handguards now. One is made by JP and the other is made by Troy Industries.
I like the new Troy Ind. made Viking Tactics (VTAC) rails. They come in 7", 9", 11" and 13" all of them include two 2" rail segments and a one 4" segment. They are priced higher than JPs but JPs don't come with the rail segments.
I have a 13" one on my 3gun rifle.