\begin{center}
    \begin{tikzpicture}
        \draw[step = 0.5cm, gray, very thin] (-7.25, -1.25) grid (7.25, 0.25);

        \node[press, /press = roller] (A) at (-3.5, -0.5) {};
        \node[anchor = south] at (-3.5, 0.25) {\textbf{roller}};

        \node[press, /press = piston] (A) at (0.0, -0.5) {};
        \node[anchor = south] at (0.0, 0.25) {\textbf{piston}};

        \node[press, /press = pelletizing] (A) at (3.5, -0.5) {};
        \node[anchor = south] at (3.5, 0.25) {\textbf{pelletizing}};

    \end{tikzpicture}
\end{center}