We have High technology dry charge batteries , built to deliver highest performance for all kinds of light and heavy duty vehicles.
Maintenance-Free Batteries should never be topped up, therefore there are no filler caps on top. The filler cap is replaced by an over-pressure valve that is normally closed. Any gas that forms ends up being recombined in the cell as water. This way there is always sufficient electrolyte in the battery. The most significant benefit of the sealed design is that no service attention is required, other than ensuring the battery is kept clean and fully charged.