Why a Spring Kit?  You use different spring strengths to adjust how much your valve opens, effecting your chronograph speed.  You balance operating pressure, hammer weight, and spring pressure to give you better efficiency and more shots per tank.

Low chrono speed?  
Maybe your stock spring is worn.  Every time the gun shoots this spring is compressed and released.  Why just buy one stock spring when you can have multiple strengths to custom fit your setup.

Is it cold outside and you are shooting CO2?  At low temperatures CO2 likes to stay in liquid form, starving your airflow.  Compensate with a stronger spring.

Is it hot as a…well you know.  Can't get your chrono speed down to the regulation field limit?  CO2 pressure increases with temperature.  Don't trim that spring, swap it out for a lighter strength.

Wow! Look at all those custom internal upgrades you have.  Now get the most from your accessories by using the correct spring strength to match your air flow and weight.
From stock to complete upgrade parts, it’s the only way to achieve the best effieceny from you gun!