The technical characteristics of the battery for each device are individual, you can check all the details and the possible time of their use without recharging with specific verified sellers.
Of course, the longer the device works offline and will not be detected by the bank's security, the better.
The skimmer is easily sent to any country and it passes the borders without inspections and customs duties, since the customs service cannot identify the device itself.
But the overhead keyboard may raise suspicions if the parcel is opened for inspection, after which the cargo may be detained.
Therefore, the sender must carefully disguise it, it is even better to send it disassembled. Once received, you will be able to collect the buttons and install them on the board.
It is best to receive parcels to the drop address for better security and anonymity.
Possession of such a device, its transfer and receipt is in itself not a crime.
But its use and application for its intended purpose in order to obtain real data of the owners' cards is a criminal offense. Therefore, be extremely careful and attentive when installing and using it. It is best to use trained drops for this, and get only the data yourself. After that, successfully record and cash out at an ATM (it is best to cash out in another country, and not in the one in which the data was received). There are a lot of proven services for cashing dump + pin.
Some useful information on scanning with contactless readers:
This Credit Card NFC Reader app is designed to read all contactless credit cards
play.google.com
www.springcard.com