If both are screwed on, it will show battery under load.
The unit has an internal battery that is recharged with the included micro USB cord.
The meter will display a --- or 0 in the first digit to the left if there is no current flow from battery to the tester, or "888" indicates error or not able to read.
The test amperage is a mere 3 milliamps to prevent any damage to the coils in the items being tested. Generally Accurate to 0.4% (but can fluxuate depending on the coil and attachment)
Orders placed before 1:00pm Eastern Time will ship same day. If the item can be added to your cart, it is in stock, on our shelves.
Shipping costs are $2.99 for First Class mail and $6.99 for Priority mail. If the First Class mail option does not show in the cart, the total order weight is over the 16oz limit.
Please contact us for an international shipping quote.