LANSING, Mich. (AP) — About 70 credit card skimmers have been found at Michigan gas stations since the first device was discovered more than a year ago.

The Michigan Department of Agriculture and Rural Development, which inspects pumps, said Thursday the skimmers can be installed in seconds and cannot be seen from outside the pump.

Criminals open pumps with keys and use the device to copy motorists’ credit card information and buy things fraudulently.

Gas station owners can change locks, install security cameras and use tamper-proof security tape to thwart the installation of skimmers.

Jamie Clover Adams, who leads the agricultural agency, encourages station owners to also increase their regular dispenser inspections.