Increases range over which spikes can be deposited.
~ BTD6 descirption
Long Reach is the first upgrade of Path 3 for the Spike Factory in BTD6. It increases the Spike Factory's range to cover an increased area from itself, spreading further along the track and potentially to other segments that were previously out of reach without assistance of the range enhancements, such as that from a Monkey Village.
While it is a cheap upgrade, it is useful in only a few niche situations, spreading the damage out for a tower mostly centralized on single area blockage. The purchase of this path also has a disadvantage in the short-term of picking between Bigger Stacks and Faster Production. The Long Reach upgrade pairs well with Path 2 upgrades overall, as the benefits become more prominent with its succeeding Path 3 upgrade, Smart Spikes.