Just had a look: mine (a leaving present from my last place of work) is a D'Addario clip-on. It clips onto the headstock of my guitar, and on the rim of the banjo, near the neck, but I take it off once it's done its job, lest it distract me or audience members.

I usually leave the battery out when it's not in use, as I've found they go flat fairly quickly (two or three months) if I don't. I *think* something in the tuner is running when the it's nominally off.