Durozone  MMB  Series Spring Return Motorized Rectangular Power Open OR Power Close 24vac Damper for Zone Control or HVAC Air Control Applications
No Damper on Ebay can match these features, at these prices! With a 5 year warranty and all metal construction, this damper beats all competition:
*No plastic drive parts or rubber belts to ever break, all metal drive linkages. 24volt AC operation
*Solid milled aluminum parallel drive blades, no rivets to come loose or rattle.
*heaviest, widest, strongest, most jam-proof aluminum frame of any competitive damper.
*5 year warranty motor with all metal gears, no plastic gears to strip, and an all metal drive shaft
*All metal, built in the USA, no plastic anywhere in drive train to ever get brittle and break – compare that to other dampers!
*Compatible with almost any brand or type of 24vac zone control system.
Standard sizes available in this “large” range, motor on either side, power open or close:
24×10
20×12  22×12  24×12
14×18  14×20  16×16  16×18
18×14 18×16  20×12   20×14  22×12
24×10  24×12
Note: When you place order,  you must specify motor on “long side” or “short side” and power open/spring close or power close/spring open.
If you don’t find the size you need here, check out our other eBay listings for the following sizes:
Small:  eBay Item #  121241592235
6×8, 6×10, 6×12, 6×14, 6×16, 6×18, 6×20, 8×8, 8×10, 8×12, 8×14, 8×16, 10×10, 10×12
Medium:  eBay Item # 121241721968
6×22, 6×24, 8×18, 8×20, 8×22, 8×24, 10×14,10×16, 10×18, 10×20, 10×22, 12×12, 12×14, 12×16, 12×18, 14×14, 14×16.
Note:
If you are using this damper connected to a zoning system board, you will want power close/spring open, If you are using damper tied directly to a thermostat, you will want a power open/spring close.
Looking for quality Three wire dampers that do not use power, except when moving? Visit our store Dampers Direct!
This damper is sold nationwide.  Damper is available in any of the sizes listed above for this price. Used for zone control systems or slave zones into unoccupied areas, these dampers are all 24vac driven and can be connected directly to a thermostat for simple control of any room or office.  Constructed of all aluminum and steel parts for long corrosion free operation,  these dampers carry a 5 year guarantee.   All damper blades ride in nylon bushings, for rattle free operation, unlike some other brands.  Dampers ship from Ohio. Dampers will be undersized 1/8 of an inch in all dimensions to slide into standard duct sizes. Dampers  are custom built to order, and ship in two to five days from order.
These are top quality dampers that are being sold factory direct by our Ebay store “Dampers Direct”, and the only thing these dampers are missing are the several levels of price markup that is usually present on this type of damper.
Our ebay store, “Dampers Direct” is run by RetroZone Inc., which specializes in HVAC zone control systems and dampers. Qualified technical assistance is a hallmark of our service, so please e-mail with any questions. If you are building a new home, trying to solve comfort problems, or energy problems, air control dampers can be a great solution!
Existing duct systems, these dampers work great!  Our Robert Shaw RS2110 or RS3110 Backlit thermostats are certified to work directly to operate these dampers, as well as any of our 24 vac transformers.
If you need multiple dampers per zone, check out our retrofit Flexdampers(tm) at “Dampers Direct”. Zoning control and air control become feasible even when you need 10 or 20 dampers in a duct system.
Steps to ordering: Rectangular Dampers:
1. Size: Choose any size above.  Message us on odd sizes, or check our other ebay adds in our store “Dampers Direct”.  When you order, we must know:
Size, side you want motor on, and power open or power close. Put this information under invoice notes, or paypal notes.
2. Choose Motor Configuration: “Power Open / Spring Close” OR “Power Close / Spring Open”: Specify what you want this spring return damper to do when power is removed, either open or close. Tip: If you are hooking this damper to a simple thermostat for direct control, order “Power Open / Spring Close”. If used in a zone control system, order “Power Close / Spring Open”.
3. Which side do you want the motor mounted on? Standard and most common is a side (short side of the damper) mounted motor, but you can also have the motor placed on the long side, or bottom, of damper, at no extra charge.
4. Choose motor voltage: Our standard dampers are 24 volts AC, which is the standard voltage in the HVAC industry. This damper will replace  any 24vac  two wire spring return damper in the industry, and most three wire dampers.
5. How to order: Just buy a damper(s) in the above size range you need, then in either ebay or paypal “notes” you will have the opportunity to specify the above size and other information; we will not ship your damper until you tell us the size, and other information.  If you order an option that costs more, just buy a damper at the price shown, and ask us in ebay to “send you an invoice” and we will correct the price before you pay.
Each damper is made to your specifications.  Dampers are shipped about 1/8 inch undersized in each dimension to insure they will fit in a standard size rectangular duct.
E-mail us with questions, we offer or can build almost any damper, including commercial grade dampers.
Returns: Buyer pays return shipping costs,  some restocking fees may apply to dampers that have been installed or damaged.  Item will ship from Fairfield Ohio or Allen Texas depending on availibility.