Medimum Duty shock spring for IRC Big Bore Rear Losi shocks.
These new strength springs are not as strong as the Red UHD ones, but stronger than the stock silver springs.  For 35cc+ billet engines or heavily upgraded cars with lots of alloy. 
 
Approx 36kg (80lb) spring rate. (weight required to fully compress)
 
Made from 100%  British Spring steel for constant spring load while under heavy load with a mat black Powder Coat finish. direct replacement to the stock silver spring.
 
includes: 2x MID Rear Springs.