Came with doublesided tape that was more than adequate to mount it.  Its liquid filled so that the ball bearing doesn't roll around very fast.  That means that it has an accurate reading, even in waves or bumpy motion.  I would definitely recommend this on sailboats or jeeps/offroaders.  Solidly made with thick plastic, it doesn't feel cheap or like its going to break.  Mounts easily, no batteries, no worries.