Assembler vats, also referred to as assemblers were nanofabrication facilities utilized by Forerunners to construct various artifacts. Assemblers ranged in size and complexity from small machines used to manufacture personal items to moon-sized foundries capable of constructing entire shield worlds and space stations. Instructions and construction templates on how to build various items were fed to assemblers for mass replication in the form of a design seed.
Following the Forerunners' demise, the Covenant would attempt to reverse-engineer assemblers, resulting in the creation of the Assembly Forges - imperfect recreations of the Forerunner technology that were susceptible to mutations in the design pattern, variance in feedstock material and transcription errors.
Known assembler vats
There were several assembler vats in the Forerunner empire;