Nockturnal Shift FIT Lighted Nocks Strobing Set of 3 Red/Blue. Super-bright LEDs and lithium batteries provide long runtime with waterproof and shockproof construction. The Shift Fit Universal model uses FIT technology and is compatible with X H S and GT arrow sizes. Each nock weighs about 25 grains and is offered in a 3-pack with over 20 hours of battery life. Specifications for Nockturnal Shift FIT Lighted Nocks: Manufacturer: Nockturnal Quantity: 3 Illumination Type: LED Size: Universal Features of Nockturnal Shift FIT Lighted Nocks: Super-bright LED illumination Lithium battery power Waterproof and shockproof construction FIT technology shift fit universal model Fits X H S and GT arrows Weight: Approx. 25 gr each Battery life: More than 20 hours 3 pack Package Contents: Nockturnal Shift FIT Lighted Nocks Nockturnal NT-833: Shift FIT Lighted Nocks Strobing Set of 3 Red/Blue