Located on the small metals shelves are a number of letter & number punches, mainly with 1/4" or 3/8" shanks, of varying sizes. Also present is a jig for using the punches on the end of the 1 1/2" arbor press, which can be helpful both for getting a consistent, deep impression & a nicely-aligned series of impressions.
Arbor press punch jig
The arbor press punch jig is an adapter for using the 1 1/2" arbor press to press 1/4" & 3/8" letter & number punches.
Punches that are 'crowned' at the top will not fit in the jig, and they are generally dangerous to use. It is advised that crowned punches be ground so that they have a slight, short taper leading onto a flat, or slightly convex, surface at the head, where the hammer (or arbor, as the case may be) will contact.
To use, insert the guide block into the sleeve & tighten screws into the tapped holes on whichever faces of the sleeve match with the flat, side surfaces of the guide block (the sleeve is made such that the guide does not need to be in any particular orientation to mate properly), so that the guide block is held securely; finger-tight should be as much force as is necessary to retain the guide block in the sleeve.
Then, insert whichever punch you are using into one of the slots on the guide block, align its top with the top of the guide block, and tighten a screw into a tapped hole on the 'front' (for the current setup) of the sleeve, so that the screw retains the punch in the guide block slot, and in the block/sleeve assembly generally. It is important that the top surface of the punch be aligned with the top of the guide block, or else the punch will be forced (by the action of the arbor press) into alignment, with the possibility of damaging the punch, the jig, or possibly the press itself.
Finally, attach the jig onto the end of the arbor; approximately 1" of clearance should remain after the above-described alignment process, and this should be sufficient for clamping onto the end of the arbor. Tighten a screw (again, finger tight should be all that is necessary) into one of the threaded holes, such that the jig is retained on the end of the arbor. Do not overtighten, as it is easy to bend (possibly permanently) the sleeve with the tightening force, and using the jig in such a bent state will likely damage the sleeve, the guide block, the press, or the punch, and will certainly result in an off-angle, unsightly impression of uneven depth.