This design is identified by a 5/16" pilot and ball groove which is nearly round. It is similar in appearance to the Industrial interchange and care must be taken to correctly identify it. 

1/4" Plugs

 
12-324
NPT
Material
Part Number
Packaging
1/4"
Steel
12-324
Bulk
1/4"
Steel
CP37
Bulk
1/4"
Steel
CP37-100
Bulk
1/4"
Steel
12-325
Carded
1/4"
Steel
12-325-2
Carded
3/8"
Steel
CP37-03
Bulk
CP38
NPT
Material
Part Number
Packaging
1/4"
Steel
CP38
Bulk
1/4"
Steel
CP38-100
Bulk
1/4"
Steel
12-335
Carded
1/4"
Steel
12-335-2
Carded
3/8"
Steel
CP38-23
Bulk
CP37-42
NPT
Material
Part Number
Packaging
1/4"
Steel
CP37-42
Bulk
CP37-44L
NPT
Material
Part Number
Packaging
3/8"
Steel
CP37-44L
Bulk

1/4" Couplers

 
C37
NPT
Material
Part Number
Packaging
1/4"
Steel
C37
Bulk
1/4"
Steel
C37-100
Bulk
1/4"
Brass
13-324
Bulk
1/4"
Brass
13-325
Carded
3/8"
Steel
C37-03
Bulk
C38
NPT
Material
Part Number
Packaging
1/4"
Steel
C38
Bulk
1/4"
Steel
C38-100
Bulk
1/4"
Brass
13-334
Bulk
1/4"
Brass
13-334-07
Bulk
1/4"
Brass
13-335
Carded
1/4"
Steel
C46
Bulk
1/4"
Steel
13-775
Carded
3/8"
Steel
C38-23
Bulk
C38-42
NPT
Material
Part Number
Packaging
1/4"
Steel
C38-42
Bulk
3/8"
Steel
C38-44
Bulk

3/8" Plugs

3/8" Couplers

C35
NPT
Material
Part Number
Packaging
3/8"
Steel
C35
Bulk
C36
NPT
Material
Part Number
Packaging
3/8"
Steel
C36
Bulk
 
CP35
NPT
Material
Part Number
Packaging
3/8"
Steel
CP35
Bulk
CP36
NPT
Material
Part Number
Packaging
3/8"
Steel
CP36
Bulk