Sides of the Brass Tunnel can be Filtered to only allow certain items to pass. If multiple outputs are available, items will be treated according to the tunnel's setting, being split by default.
The Value Settings Screen can be accessed from the top of the Tunnel. It is only viewable if the Tunnel has other outputs or is connected to other Tunnels.
Setting
Function
Split
Item stacks will be split between available outputs.
Forced Split
Only splits items when all outputs are available.
Round Robin
Alternates outputs in each available tunnel.
Forced Round Robin
Waits for unavailable outputs in a round robin sequence to become available.
Prefer Nearest
Chooses an output nearest to the input for as long as it is available.
Randomize
Output is randomized.
Synchronize Inputs
Output all at once, stalling when items are missing. Synchronized tunnels may not draw from adjacent tunnels, so it may be necessary to have splitting tunnels placed before them.