It has a 20 1/2" top rail and two 5" rails at 45 degree angles. It actually weighs a lot less than I thought it was going to and it was easy to install. It has a flat black finish whereas the 870 is more of a dark grey. Having said that, it doesn't quite match the finish of the 870 if that matters to you but I think it looks great just the way it is. For what you pay and what it allows you to do, this is a fantastic piece of equipment. I mounted Magpul sights onto it and I absolutely love it! Use a Mesa Tactical low tube or high tube adapter (I use the high tube) and you CAN use shell carriers with this. Mesa makes adapter mount sureshells and I have two of them along with the Warhammer on my 870.
Pros: Lightweight, looks AWESOME!
This review was written in the old system and had content requirements that are different than reviews written today.