Briley HONEYCOMB Benelli/Breda/Retay/Sauer Semi-Auto Shotgun Magazine Extension 12 Gauge -

This extension allows you to increase the ammunition capacity of the shotgun. The extension is made of tough 6061 aluminum. This allows the tube to have a large wall thickness to improve rigidity without compromising overall weight. The tube screws down on the magazine and locks the fore end in place. The extension is supplied with a magazine tube spring. 

Fits:
Benelli M1, M2, Super Black Eagle I II & III, and Super 90
Breda

Retay Ace

Sauer SL5

Does not fit:
Benelli M2-G1

Overall Length 
+6 shots - 13.500"

Outer Diameter 1.062"