Bathtub

A bathtub is an object that appears in most of The Sims games. The primary use is improving a Sim's hygiene, as well as other traits or moods.

Some bathtubs have shower fixtures, but most do not.

The Sims
Bathtubs in The Sims (and expansions) also provide Comfort.

The Sims 2
Bathtubs in The Sims 2 (and expansions) also provide Comfort.

The Sims 3
Bathtubs in The Sims 3 (and expansions) also provide stress relief.

The Sims Medieval
In The Sims Medieval, bathtubs provide a positive buff.