PS, 990 Sport Series shock set. 12.5". STD Duty. Black 91-92 FXD/B/C

With bushing. 
990 Sport series - Best. 
Based on the 970 series but designed towards aggressive sport/race inspired riding. No other shock offers this much tuning adjustability. Features include a linear rate coil spring, a 0.4" adjustable eyelet height and adjustable threaded preload, a piggyback reservoir (remote for Touring) has a knob to adjust both rebound and high & low speeds compression damping. Featured in a lightweight aluminum body the high-pressure monotube with deflective disc damping routed through two unique circuits delivers a consistent feel through the damper stroke for improved performance and stability. A new and improved engineered jounce bumper features a captured design to help smooth and control bottoming out. Each shock is hand-built & dyno tested to deliver real world performance.

What are Progressive Suspension's 'STD Duty' vs '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.