Worker Swift & Harrier Upgrade Spring 1.6×300

This upgrade spring can greatly improve the worker swifit and worker harrier blasters' velocity by 80-90 FPS. 

Specifications:

Brand: worker nerf.
Material: steel.
Wire diameter: 1.6mm.
Size: 300*11mm.
Compatibility: worker swift and harrier foam dart blasters.
Package includes: 1x worker 1.6*300 spring mod.