20% Underdrive modification to your secondary , must be used with our Overdrive Primary and KWI Weights. 
If you already have our Overdrive Primary with KWI weights you are all set  however to ensure the new under drive modification works properly we need to get your Primary back to go through it to ensure it has all the latest revisions to work properly with the Underdrive Secondary, there is no charge for this other than return shipping, If you do not have the KWI Weights we can install the weights and rollers with titanium roller washers for $500 or the complete KR190X Kit which also includes new slider buttons for $650.
In addition the the modifications we inspect and service the secondary, if the seals or bushings are worn the cost to replace them is as follows.
Bushings (2) $28 ea.
Seals (2) $13 ea.
O-Rings (3) $4 ea.