PS, 465 Series single shock 309mm. STD Duty. No RAP

12.2" (309mm) -24mm lower; Standard springs; Black anodized. Great replacement single shock. Manufactured with a high pressure nitrogen filled black hard anodized aluminum body, with a large 46mm bore and deflective disc damping. Comes with Regular threaded or RAP (Remote Adjustable Pre-load) located behind the left passenger peg, for easy accessible adjustments. Rebound damping is 5-position adjustable. Available in stock, over and undersize lengths to accommodate the various stock Softail model lengths. 

What are Progressive Suspension's 'Heavy Duty' shocks? 
If you are a lightweight rider with a lightweight passenger, STD Duty is probably your best choice, heavy duty shocks will give you a harsh ride. For Big Guys & Gals with a lot of baggage, Heavy Duty springs are the way to go. Heavy Duty is not better, it's different.
Heavy Duty shocks or springs are recommended to be used on motorcycles that are operated at or near the manufacturers maximum load rating over 50% of the time.