Pfister’s PermaBalance valve represents a large jump forward in tub and shower valve technology. With a new brass stem, larger ceramics, a more flexible install depth for shallow wall installations and a high-precision spool balancing unit, it is the company’s best in-wall valve yet. It offers years of trouble-free service while still being able to pressure-balance down to flow rates as low as 0.5 gpm at the showerhead.  .