This product is actually extremely good. It's durable, very well made. It looks great and can be very intimidating. The finish is nice and matches most marker paintjobs and it just slips onto pretty much any barrel without modification. Easy to install. All around, it's a very good product, but it could be better.
The front ring (the solid plastic ring with the center line ridge) tends to fall out. I know, because mine has several times. I wound up having to wrap black hockey tape around it a couple of times to keep it in place. The rear ring isn't universal. If the barrel has any kind of a flange, like a Proto barrel for example, the ring won't pass over it. I solved this by cutting hte ring in one spot so it can open up. They might want to think about that as a standard piece.
Where the problem comes in is customer service. It's EXTREMELY poor. They don't return e-mails, act like you're disturbing them with petty issues if ytou call. It's VERY poor customer service.
This review would've gotten a much higher rating if the customer service was better. I consider the product, the comany and it's way of dealing with it's customers when reviewing a product. Mainly because at some point you may have to call customer service and a product is only as good as it's support.