It is in seconds. I personally set mine at 8 seconds except for auctions ending on Sunday PST 5-8:30 and on the hour, half, and quarter. At those times I add 10-15 sec. Remember to always snipe your max! The biggest bid wins!
It's weird because I had mine set to 3 seconds for a few days but thought better of it. Now it won't even let me do 3 seconds, 5 is as low as it will go.
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