Ambire Wallet's "Gas Tank" is a feature that enables Ambire Wallet users to benefit from savings on transaction fees processed through the Relayer, or in other words it allows users to pre-pay for gas fees.
What is the Relayer?
The Relayer is a back end service, which is responsible for broadcasting transactions to the network. It exists because of the gas abstraction mechanism which allows users to pay transaction fees in any token and enables the Relayer to automatically manage gas fees. Therefore, the Relayer saves Ambire Wallet users a lot of fees in total, but a small additional fee is paid whenever it is used.
How does the Gas Tank work?
The Gas Tank works like a pre-pay mechanism, crediting the Relayer in advance through one deposit to the Relayer's address, instead of depositing (which requires additional fee) with each transaction. When you enable the Ambire Gas Tank and pre-pay through token deposits, you will no longer be charged gas fees for each transaction to the Relayer, since you will already have tokens there. This means you will pay less for every new transaction that needs to be executed, while the Gas Tank feature is active, therefore saving significantly over time.
Another saving mechanism of the Gas Tank is the Cashback function. When you request a transaction, you are presented with an estimate fee, based on the gas rates at the time of creating the transaction, which in many cases might be different from the real fee paid in the end to the network, when the transaction is mined. When using the Gas Tank, this difference is also returned to the user and we refer to it as "Cashback".
How much fees does the Gas Tank save?
How much of the gas fees will be saved from the Gas Tank depends on many factors, like how busy the network is at this moment, what is the trend of the gas fees (going up or down) and more. This is the reason why the "Saved" and "Cashback" amounts are different for each transaction.
In the Gas Tank menu you will see your overall savings on the current network, both from "Saved" and "Cashback".
In the Transaction history menu, for each transaction when the Gas Tank was used, you will see a "Total saved" amount. It is a combination of those two components. If you hover on it - you will see breakdown of the savings from this transaction - "Saved" and "Cashback".
You can find more information on how to top your Gas Tank here.