A very good product, and probably the best (and possibly only) way to use a sling with your P90. Everything you need to mount the Sling adapter to your P90 is included in the package. The way it works is that the there are two screws at the bottom of the adapter (can be seen in the picture). You first have to unscrew the two screws out from the holes on the opposite side of the adapter. You then pull the screws out, and slide the adapter up on to the body of the P90 so that the Echo 1 trades read normally. This adapter is mounted on the bottom right area of the P90 where there is the long slit. To secure it, you put the screws back into their respective holes on the adapter, making sure they go through the slit, and back into their holes on the opposite side of the adapter where they screw in. The actual sling swivel can be mount on either the left or right side, or the bottom if you choose too. This is a very good design, and creates a very sturdy mount, because one of the only realistic ways this mount could fail is for the actual slit its mounted to to crack.
Easy mounting and design
3 different places to choose where to put the swivel
Worth the money
Slightly expensive, but worth the price
Over all, a great buy, and one anyone should consider if they want to use a sling with a P90