DUCT STARTING COLLAR - 500-501

500 - OFFSET STARTING COLLAR - 2" RISE
 

DUCT              PLENUM        ITEM             QTY
SIZE             CUT OUT                            
 8 X 8..........12 X  8.........3000...............6
10 X 8..........12 X 10.........3001...............6
12 X 8..........12 X 12.........3002...............6
14 X 8..........12 X 14.........3003...............6
16 X 8..........12 X 16.........3004...............6
18 X 8..........12 X 18.........3005...............6
20 X 8..........12 X 20.........3006...............6
22 X 8..........12 X 22.........3007...............6
24 X 8..........12 X 24.........3008...............6

501 - STRAIGHT STARTING COLLARS
 

SIZE          ITEM               QTY
 8 X 8........3012.................6
10 X 8........3013.................6
12 X 8........3014.................6
14 X 8........3015.................6
16 X 8........3016.................6
18 X 8........3017.................6
20 X 8........3018.................6
22 X 8........3019.................6
24 X 8........3020.................6
500 & 501 starting collars - both fittings have wide flanges and tabs for locking into plenum opening.  The 500 style has a larger throat area at the plenum opening for increased airflow efficiency.  Using the style 500 vs. 501 will save 25 effective feet.  

Champion manufactures both radius and square throat duct elbows.  Radius elbows are more efficient but have larger bend radius which may preclude their use in limited space.  The square throat type fittings make abrupt direction changes in limited space but may cause additional effective lengths of up to 75' depending on duct size.