Kohler K-45209 Guia De Instalacion página 4

Roughing-In - Upper Supply Connection
Measure the distance between the 1/2"-14 NPT elbow and the
finished wall surface. The distance must be between 1-3/8" (35
mm) and 2-7/8" (73 mm). The shower column connection will not
seal properly if the distance exceeds 2-7/8" (73 mm).
1184491-2-A 4 Kohler Co.