Most Wirt pens do not have clips. Clips are occasionally seen on a non-screw cap pen, but mostly are seen on pens with threaded caps.
In my collection, the B&H clip is present on three pens: a Wirt Simplicity pen (screw cap), a black hard rubber lever filler (screw cap), and a safety with ink shut off (screw cap). This logo matches Byers and Hayes logos seen on otherwise normal Z clips on their pens. Strangely I do not easily find pictures of any B&H pens with the type of B&H clip seen on Wirt pens.
The “WIRT” imprinted simple Z clip is present on all four of my celluloid Wirt pens. [The prior Wirt site by Ron Dutcher states that this clip was on larger #5 and #6 hard rubber lever pens, and that the plain Z clip was on the smaller sized #3 and #4 pens. ]
The VV clip was on a lone cap, no pen. The cap is not threaded.
The roller clip is marked “US PAT 1914” and “GER SILVER”. The Logo in between appears to be “WHH.” It belongs to a plain hard rubber pen that lacks a Wirt barrel imprint. The barrel is marked “INTERNATIONAL LIFE –ST LOUIS MO–“
The plain Z clip is on a black chased hard rubber pen, standard sized. There was no nib, but size #3 or #4 would seem appropriate.