The Neptonics Wide Mouth Euro Trigger Mech is machined out of solid stainless steel and features strong, durable internal components. Like all of our trigger mechanisms, the Euro Mech is designed to offer a smooth and consistent release every time. The extra-wide housing allows the shaft & mono to slide into the trigger mechanism. Inside the housing, the geometry has been fine-tuned to offer the highest level of performance. If you are building a speargun that uses Euro Shafts, this trigger mech is perfect; it fits all euro-style shafts.