Tubular Bags as they are commonly called are oxide holders for the tubular battery positive plate. The spine grid is inserted in one end of the PT Bag and filled with oxide from the other end, completely enclosing the spine grid, which makes it protected from corrosion.
The open end is locked with a bottom bar and you have a tubular positive plate – which are very robust and have a very long life. They are used in all tubular batteries like – UPS, Inverter batteries traction battery, in high-end industrial applications like Railway Locomotive Battery, Train Lighting batteries and Signaling battery, also in High-performance Stationary cells – requiring a Zero Defect, Zero Failure Tubular Bag. It is also used by tubular battery manufacturers and for Tubular Gel battery applications both deep cycle batteries demanding a robust construction of the Tubular Bag.