This mod adds variants of standard underground belts.
- long underground belt - unlocked at Logistics 2 - length 7 - crafted from underground belt
- very long underground belt - unlocked at Logistics 3 - length 9 - crafted from long underground belt
- long fast underground belt - unlocked at Logistics 3 - length 9 - crafted from fast underground belt
With Space Age, it also adds:
- super long underground belt - unlocked at Turbo Item Belt - length 11 - crafted from very long underground belt
- very long fast underground belt - unlocked at Turbo Item Belt - length 11 - crafted from long fast underground belt
- long express underground belt - unlocked at Turbo Item Belt - length 11 - crafted from express underground belt

These belts are crafted in 0.1 seconds.

The idea is, by unlocking latter belt technologies, you also unlock longer belt lengths. But not always you want to use resources to place faster belts when there is no need for them. So here come those longer variants - they are basically free upgrades of the 'base' underground belt.