This mount is made for people that want to run their ERECT9R on a fixed barrel firearm.

Specs: 

1/2-28 Direct Thread

• 17-4 Stainless Steel 
• Head Treated
• 1.12 Oz

M13.5-1LH Direct Thread

• 17-4 Stainless Steel 
• Head Treated
• 1.12 Oz

If you have a fixed barrel firearm DO NOT run your ERECT9R with the piston.