Euzonoi could be considered either the lightest of melee troops or heaviest of the psiloi skirmishers. They carry javelins, a sword or dagger, a thureos shield and helmet, if it can be afforded.
The euzonoi are the mainstay, light troops of Hellenistic armies. Sacrificing heavy arms and armour for mobility and range, they are akin to the peltastai of the Classical period. Like the peltastai, they may be understood as either the lightest of melee troops or the heaviest of the psiloi. Drawn primarily from the young men and burdened only by a light exomis, they are very mobile. Their armament consists of several javelins and a sword or dagger. To increase their survivability in skirmishes and melee, they carry the thureos shield, and those with access to them also wear helmets. Thus they are armed and trained for the express purpose of excelling as skirmishers, and while they are able to engage in melee, they are too lightly armed and armoured to last long against heavier or better-trained opponents without suffering severe casualties.
The euzonoi became one of the most important components of Hellenistic armies over the course of the 3rd century. The Galatian invasions in the early third century introduced the thureos to the Hellenistic world. By mid-century, many Hellenistic cities, confederations and kingdoms had begun equipping some of their soldiers with the new shield. Offering greater protection than the pelte and more affordable than the aspis, the thureos suited light troops well. The euzonoi were important contingents in practically any army in the Hellenistic period. For local operations, they often equalled in number the heavier contingents, and soldiers that performed well before their kings, generals and fellow soldiers could hope to win honour and advancement. They often undertook roles that utilized their mobility, seizing heights, attacking flanks, or harassing enemy troop formations.