Progressive Suspension FORK SPRING KIT 11-1569 939800 Hidden breathers are O-ringed at

Hidden breathers are O-ringed at the heads and exit out the mouth of the injector/carb to provide efficient engine breathing

Black housing

2009 Harley-Davidson Sportster Custom - XL 883C

and designs

Progressive Suspension FORK SPRING KIT 11-1569 939800 Hidden breathers are O-ringed atProgressive Suspension FORK SPRING KIT 11 1569 Progressive Suspension Fork Springs High quality, high performance replacement fork springs A Progressive Suspension rate spring has the advantage of a rising rate resistance to compression The benefit is the spring can be soft enough at the start of the travel to offer a "plush" ride, yet firm enough at the end of the travel to soak up the big bumps Spring rates have been chosen to reduce front end dive