Aglet

The speed bump is small enough that you will not feel it on its own. Its job is early: you dig one out of a surface chest before you have boots of any kind, and a slightly faster walk makes the first hours of running between spawn points less tedious. Once Hermes Boots turn up it is outclassed on its own merits.

It feeds the boots chain that ends at Lightning Boots, so the one you found at hour two is still working in Hardmode. If you missed it, the Skeleton Merchant carries it, but only when the moon is new, so you may need to wait out several in game nights for the right phase.

An aglet is the little plastic sleeve crimped onto the end of a shoelace so the threads do not unravel. Terraria has a habit of hanging movement bonuses on footwear, and this is the smallest example of it.