The Speed Boots are a relic acquired in Castlevania: Lords of Shadow - Mirror of Fate. They allow Trevor to jump higher.
In game Description: Designed by the Toy Maker to give war messengers greater speed, this prototype perfectly combines complicated engineering with the purity of its magic components. All that is required is to step forward twice to activate the propulsion mechanism and disappear in a cloud of dust.
The Speed Boots is gained from a purple pedestal on the very top of the Clock Tower (Mirror of Fate).