Duct

Duct is a basic item-transport block that pushes items forward along its facing direction. It functions as a one-item buffer: a Duct can hold only a single item at a time and will pass that item onward when the next block accepts it. Ducts do not consume power or items while idle and have no continuous resource drain.

The primary role of a Duct is forward transportation and short-term buffering in compact layouts where a single-slot holding space is sufficient. Because the internal storage is limited to one stack unit, they are best used for tight, deterministic item movement rather than for mass storage or smoothing large throughput spikes. The source guide recommends using a rolling-log style pull line for feeding Ducts efficiently (literal translation: “rolling log”), which implies placing pull-oriented conveyance before a Duct to keep it supplied without jamming.

Ducts accept inputs from the side as well as from the back. Because of this, they can unintentionally receive items from neighboring blocks that produce or output items into adjacent tiles. To prevent accidental side-inputs, place dedicated routing blocks or conveyors that control the direction of item flow between a producer and the Duct, or use spacing and orientation to avoid unwanted contact. Pay attention to adjacent manufacturers and mass-producers: a Duct next to such a block may pick up outputs if that block faces the Duct or if a connector allows side flow.

Ducts have no active consumption, making them cheap to operate and simple to chain into long lines where only single-item buffering is needed. When upgrading or applying Reinforced -related improvements, note the listed enhancement: Overspeed (double-tech), which implies a speed-focused upgrade path when Reinforced versions or upgrades are available. Use Ducts where you need deterministic, low-latency transfers and pair them with directional conveyors or routers to avoid unintended side-inputs.