| LH 22.135 | Post Office Box (Constantan Coil) Plug Type 3-Ratio (Routine Quality) |
| LH 22.137 | Post Office Box (Constantan Coil) Plug Type 4-Ratio, Ring Type Brass Block (Routine Quality) |
Lab Equipment Manufacturers & Wholesaler Online | Labohouse - 
| LH 22.135 | Post Office Box (Constantan Coil) Plug Type 3-Ratio (Routine Quality) |
| LH 22.137 | Post Office Box (Constantan Coil) Plug Type 4-Ratio, Ring Type Brass Block (Routine Quality) |