The Thunderglo Lighted Nocks are constructed of a polycarbonate blend nock with an aluminum shaft. It features bright LED illumination by an auto-on system when the nock is shot and stays on until the user unclicks the nock. It's universal collars fits arrow shafts (G/X/H/S)
Specifications:

Type	Crossbow
Model	Thunderglo
Length
Weight
Draw Weight
Arrow Length
Color	Green
Misc
Quantity	3 Per Pkg
Fiber Type
Magnification
Material	Polycarbonate/Aluminum
FPS
Scope Type
Vane Type