The Abomination Handler Gear was built for the Ytarrans that handle Abomintations. Armor-wise it seems to be heavy clothing with a lot of additional stuff, enchanted from the Ytarrans to give the protective properties of an enchanted chainshirt. From the circumstances in which the Party found it, they may have been five other sets of Handler's Gear, probably taken away or disenchanted to create other stuff.
Polaon Controller insisted that the Handler's Gear had to be taken before The Party entered the room with the Beholdroid, but it was taken after they fought it. Morduval's suit later ate the Handler's Gear while Angel slept, making it one of the many items of clothing she can "swap in" when necessary.