The cheaper one is sold and shipped by Amazon, while the more expensive one is sold and shipped by KustomPainting and it is not unusual to see Amazon do some weird things with pricing. If they are both the same part number then they are the same. They are both red. The KustomPainting one appears to have a blue paddle handle, but this may actually be a protective plastic peel off on the chrome handle that was not removed for the pic.
Below are the specs from the Dynabrade web site. Sorry, cannot link to the page, its java or something and the link would only take you to the whole catalog.
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21035
6" (152 mm) Dia. Non-Vacuum Dynorbital-Spirit Random Orbital Sander
.25 hp, 12,000 RPM, 3/16" (5 mm) Dia. Orbit, Rear Exhaust
Includes low profile, premium urethane weight-mated sanding pad. Optional vacuum conversion kits are available to easily convert non-vacuum tool to self-generated vacuum tool or central vacuum tool. Grey lever identifies 3/16" (5 mm) dia. orbit, used for general sanding.
Drop-In Motor available (sold separately) to reduce costly down-time associated with routine maintenance. More Power - True 12,000 RPM air motor. Floating rotor utilizes five blades, producing more usable power (.25 hp/186 W). High-strength, composite rotor has better lubricating qualities, allowing blades to last longer. Less air (2CFM/14 SCFM/396 LPM) is used more efficiently to maintain maximum power.
Comfort Platform provides additional hand and wrist support, further enhancing operator comfort. Also offers increased protection against cold air exhaust. (NOTE: Comfort Platform is removable.) Order 59330 Comfort Platform separately, to install on existing tools!
Throttle lever recesses into housing grip when depressed, eliminating pressure-point on operator's palm. Dynorbital-Spirit lever is made from composite material to insulate against cold air. Lever is color-coded to designate tool orbit. Easy maintenance and vacuum conversion. Muffler elements are easily changed for convenient maintenance. Low Sound Levels. Muffling system reduces exhaust sound levels.
Speed Control allows thumb-control regulating of tool speed. Lighter air-motor assembly, ideal for vertical and overhead sanding applications. Precision one-piece motor shaft and counterbalance. High-quality Double Row Pad Bearing, protected by unique V-Seal, improves bearing life and ensures reduced vibration. Perfectly-balanced, weight-mated sanding pad with one-piece hub design. Dynabrade premium urethane pads offer smoother operating performance and minimal vibration.
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Videos in the description box for this sander.
http://www.dynabrade.com/dyn10/videos/videocont.php?pfx=WEB&no=145
http://www.dynabrade.com/dyn10/videos/videocont.php?pfx=WEB&no=37
http://www.dynabrade.com/dyn10/videos/videocont.php?pfx=WEB&no=41
Charles