Rhythmic pulsing of voltmeter

Is that mechanical or IC? O'reillys also had one for 17.99 but it didn't specify whether it was mechanical or IC so I'm assuming it's mechanical. The 17.99 and the 22.99 were both BWD and the IC version was AC/Delco. I like Duralast too. Don't guess there's any big difference or pros/cons on the IC version vs the mechanical version so probably go with that Duralast. Thanks!