PS, 494 Sport series shock set. 12". STD Duty. Black Bearing type.

A true sport performance shock at heart with competitive price. The Progressive Suspension 494 Sport Series Shocks feature a high-pressure nitrogen charged monotube design with deflective disc damping technology, hand threaded preload, and a rebound adjustment to dial in the ride. This technology coupled with a progressive rate spring allows for a consistent performing shock in a variety of real-world scenarios. An engineered jounce bumper with a built-in metal cup helps smooth out and control bottoming. From pounding the pavement around town to hammering around the tarmac on your next race day, the 494 is the perfect choice for your performance demand! Every shock is hand-built, tuned and checked for a bolt-on non-issue shock experience. 
- High-pressure monotube design 
- Deflective disc damping technology 
- Jounce bumper with a built-in metal cup against bottoming out 
- Hand adjustable spring preload 
- Progressive rate spring. 

What are Progressive Suspension's 'STD Duty' vs 'Heavy Duty' or 'Super 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. In short: Standard (good for combined rider weights up to 250 lbs / 113kg), Heavy-Duty (250 lbs / 113kg to 350 lbs / 159kg) and Super Duty (350 lbs /159kg and up).