.
Silica I
0-1740-xxx

Silica I (4 Pos Valve)
0-1741-xxx

Silica II
0-1750-xxx
The third set of numbers xxx can mean a color or a variation on the model.
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M M 1300 2 Pos
0-1700-013

MM 1300 4 Pos
0-1701-013
MM 1600, 4 Pos Valve
0-1700-016
1997 and before

MM1600, 6 Pos Valve
0-1701-016
1997
MM1600, 6 Pos Valve
0-1701-016
After 1997
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MM1900, 6 Pos Valve
0-1702-019
MM2200, 6 Pos Valve
0-1702-022
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