The plaque, measuring roughly 68 centimetres high by 47 centimetres wide, sits within a chamfered recess, that is, a neatly cut angled surround, on the west face of the most easterly pier. Carved in relief at its centre is a heraldic shield bearing the Hackett family arms.

The Hackett device is itself worth a moment's attention. The arms display three hakes, large pike-like fish, shown hauriant, a heraldic term meaning upright, as though leaping. It is a punning coat of arms, the fish chosen specifically to echo the family name, a device known as canting heraldry and common among medieval Anglo-Norman families who had settled in Ireland. Running along the top and bottom of the plaque, and across the top of the shield, is an inscription in Latin rendered in Black Letter script, the dense angular lettering typical of medieval stonework. As transcribed, it reads: SCUTUM MAGISTRI REDMONDI HACKET ET EDMONDI FILLII EJUSDEM FABRICATORII ISTIUS ECCLE, meaning roughly "the shield of Master Redmond Hacket and Edmund his son, makers of this church." Below the central fish, the family name HAKET is carved again, as if to leave no doubt. Floral motifs fill the lower corners of the plaque, framing the inscription with a small decorative flourish. The monument is therefore not primarily a funerary marker but a donor inscription, recording the Hacketts' role in building or substantially funding the church itself, a form of permanent acknowledgement that was both pious and proudly self-commemorating.