Model or Range 1221, 2 & 3 Scale
Length "A"		 1221 & 2 Scale
O.A. Length "B"		 1223 O.A. Length "B"

Inches H2O Millimeters H2O W/M D W/M D W/M D

8 (4-0-4)
12 (6-0-6)
16 (8-0-8)
20 (10-0-10)

24 (12-0-12)
36 (18-0-18)

M200 (100-0-100)
M300 (150-0-150)
M400 (200-0-200)

M600 (300-0-300)


1000 (500-0-500)

12-1/4
16-1/4
20-3/8
24-1/4
27-7/8
28-1/4
40-1/4
43-5/8

14
18-7/8
23-5/8
28-1/2
32-7/8
33-3/8
47-7/8
52

15-1/4
19-1/4
23-1/4
27-1/4
30-3/4
31-1/2
43-1/4
46-1/2

17
12-3/4
26-1/2
31-1/2
35-3/4
36-1/4
50-3/4
55

18-1/2
21-1/8
26-1/8
30-1/8
33-5/8
33-3/8
46-1/8
49-3/8

19-7/8
24-5/8
30-3/8
34-3/8
38-5/8
39-1/8
53-5/8
57-7/8

NOTE: Not recommended for vacuum service above 5 in. Hg (68 in w.c.).