Comparison : Item # 5406-P-02, 1/8 Inch (in) T1 (NPTF) Carbon Steel Male Hex Head Plug
Item # 5406-P-04, 1/4 Inch (in) T1 (NPTF) Carbon Steel Male Hex Head Plug
Item # 5406-P-06, 3/8 Inch (in) T1 (NPTF) Carbon Steel Male Hex Head Plug
Item # 5406-P-08, 1/2 Inch (in) T1 (NPTF) Carbon Steel Male Hex Head Plug
Item # 5406-P-12, 3/4 Inch (in) T1 (NPTF) Carbon Steel Male Hex Head Plug