About 65mm long with body extended and both pairs of tentacles extended.
About 50mm long with body and tentacles retracted.
I had a pet slug a few years ago. It slithered into the laundry at night for months. One dark night there was an unsettling squelch underfoot. Ah well, no more (minor) slime trails. A few weeks later another came. Slug bait. Accidental of course, who would poison their late pet's family? Now, another in the laundry.