This is the new Strike Single Folder - Stock Edition. You might already be familiar with Strike Industries' Strike FSA Dual, a modular folding arm system that can fold left or right with interchangeable stock and stabilizer end pieces. While the new Stock Single Folder still uses the same arm and stock end piece as Strike Industries' Dual Folder, it features a reinforced steel hinge instead of aluminum, making it highly durable. The fitment is precise, with minimal to no play when extended or folded. Although this folder only folds to one side, it can do so at any time without reconfiguration or pressing a button.