Micro Porous Vent Plug To Suit To Lead Acid Batteries 8 Volt / 500 Ah As Per Rdso Drawing No. Skel-4020/ A, Alt-3 Sheet No-2. Make: Exide / Celtek / Microtex Or Equivalent For Providing In Locomotive Batteries. Note: 1 No Sample To Be Supplied For Approval Before Effecting Bulk Supply. ]