CORE RC Hi Response springs for 1/10th Touring and FWD cars.Developed by Schumacher engineers and high level drivers, these new springs bring a new dimension to 1/10th Touring.These springs have been designed to improve responsiveness of the cars compared to the competition.Featuring less coils and having a thinner wire diameter they offer over a 40% weight saving over the competition, a significant 5.2g per set of 4.CORE RC provide a wide linear range from 1.9 N/mm to 3.5 N/mm and also a progressive spring measuring 2.2-2.919mm in length.Three easy to buy, pairs of 4 are available as sets;CR852 Soft; including 1 pair of 1.9, 2.1, 2.3 and 2.2-2.9 progressive.CR853 Medium; including 1 pair of 2.5, 2.6, 2.7 and 2.8CR854 Hard; including 1 pair or 2.9, 3.1, 3.3 and 3.5