This spring has more tension than a stock spring, for easy use and less arcing from your cars. They change an AML shoe from 1.5 grams of tension to 2.2-2.3 grams of tension, which is the starting point for most fray racers. This is just another easier way to make your cars faster, easier and more affordable than all other competitors.

Cost is
E84 1 pair - $1.00
E84A 10 pair - $9.00