$\displaystyle \rho sin \phi = 1$ is given in spherical coordinates. Interpret geometrically.

How can I approach this problem? I know that

$\displaystyle \rho = \sqrt{x^2+y^2+z^2}$

$\displaystyle tan \theta = \frac{y}{x}$

$\displaystyle cos \phi = \frac{z}{\sqrt{x^2+y^2+z^2}}$.

I tried plugging in $\displaystyle \rho$ into the equation but that led me nowhere, and I don't know what to do with the $\displaystyle sin \phi$.