What does it do?
Black to Bright at 131F (55c)
Know when your barrel is too hot to safely handle or store.
Color activates at common bullet drift temperatures.
No more guess work.
Insanely bright & awesome colors.
Makes crush washers cool (at least…as cool as possible).
No more stupid:

Hand hovering
Barrel tapping
Spitting (people really do this…stop it)

Note: extended operation over 450ºf can result in breakdown of thermochromic properties.

***Note about Installation***

If more than 180 degrees of tightening is required for timing, please use shim. Over tightening can cause damage to the Spark™ and it’s coating.