The Tac-79 comes with one 4" Picatinny Rail mounted at the 12 o'clock position on the breech end of the barrel.
The barrel also has a 6" rail on the bottom.
The basic specs of the Tac-79 With Folding Stock Adaptor are as follows:
Designation: Launcher, 37mm, Single Action, Exposed Hammer, Top Break, and comes with the a side folding stock adapter. Release is simple: there is button on the side that, when depressed, releases the stock and allows it to swing 180 degrees to the left side of the weapon.
Country of Origin: USA
Manufacturer: Ordnance Group LLC, Sarasota Florida USA