\paragraph{Anchors}

\begin{center}
    \begin{tikzpicture}
            \draw[step = 0.5cm, gray, very thin] (-4.25, -2.25) grid (4.25, 0.25);
            
            \node[gas filter] (Bempty) at (-1.5, -1.0) {};
            \node[anchor = south] at (0, 0.25) {\textbf{\textbackslash node[gas filter]}};
            \node[gas filter] (B) at (1.5, -1.0) {};
            \node[cross] at (B.center) {};
            \node[anchor = west, font = \tiny] at (B.center) {C};
            \node[cross] at (B.east) {};
            \node[anchor = west, font = \tiny] at (B.east) {E};
            \node[cross] at (B.west) {};
            \node[anchor = east, font = \tiny] at (B.west) {W};
            \node[cross] at (B.north) {};
            \node[anchor = south, font = \tiny] at (B.north) {N};
            \node[cross] at (B.south) {};
            \node[anchor = north, font = \tiny] at (B.south) {S};

            \node[cross] at (B.northeast) {};
            \node[anchor = west, font = \tiny] at (B.northeast) {NE};
            \node[cross] at (B.near northeast) {};
            \node[anchor = west, font = \tiny] at (B.near northeast) {nNE};
            \node[cross] at (B.far northeast) {};
            \node[anchor = south west, font = \tiny] at (B.far northeast) {fNE};

            \node[cross] at (B.northwest) {};
            \node[anchor = east, font = \tiny] at (B.northwest) {NW};
            \node[cross] at (B.near northwest) {};
            \node[anchor = east, font = \tiny] at (B.near northwest) {nNW};
            \node[cross] at (B.far northwest) {};
            \node[anchor = south east, font = \tiny] at (B.far northwest) {fNW};
            
            \node[cross] at (B.southeast) {};
            \node[anchor = west, font = \tiny] at (B.southeast) {SE};
            \node[cross] at (B.near southeast) {};
            \node[anchor = west, font = \tiny] at (B.near southeast) {nSE};
            \node[cross] at (B.far southeast) {};
            \node[anchor = north west, font = \tiny] at (B.far southeast) {fSE};
            
            \node[cross] at (B.southwest) {};
            \node[anchor = east, font = \tiny] at (B.southwest) {SW};
            \node[cross] at (B.near southwest) {};
            \node[anchor = east, font = \tiny] at (B.near southwest) {nSW};
            \node[cross] at (B.far southwest) {};
            \node[anchor = north east, font = \tiny] at (B.far southwest) {fSW};
    \end{tikzpicture}
\end{center}

\paragraph{Options}

\begin{center}
    \begin{tikzpicture}
        \draw[step = 0.5cm, gray, very thin] (-7.25, -2.25) grid (7.25, 0.25);

        \node[gas filter, /gas filter = bag] (A) at (-3.0, -1.0) {};
        \node[anchor = south] at (-3.0, 0.25) {\textbf{bag}};

        \node[gas filter, /gas filter = bed] (A) at (-1.0, -1.0) {};
        \node[anchor = south] at (-1.0, 0.25) {\textbf{bed}};

        \node[gas filter, /gas filter = hepa] (A) at (1.0, -1.0) {};
        \node[anchor = south] at (1.0, 0.25) {\textbf{hepa}};

        \node[gas filter, /gas filter = belt] (A) at (3.0, -1.0) {};
        \node[anchor = south] at (3.0, 0.25) {\textbf{belt}};

    \end{tikzpicture}
\end{center}