Guarder bore-up air-seal nozzle

Guarder's improved, sealed nozzle for M4 / M16 station models. This model is a so-called bore-up model, which allows for a larger air flow from the cylinder to the hop-up unit. The feature is implemented by expanding the inner diameter of the nozzle, so this nozzle is only suitable for use with corresponding Bore-up cylinder heads. When installed in a regular cylinder head, this nozzle will be loose.