Raising the bar again, the new syncroFloatR IV runs and feels better than ever. With a touch of support for the mild pronator, this is a smooth, well cushioned and responsive shoe for the efficient runner. 1:1 Seamless Upper creates an unparalleled fit with a seam free interior. 1:1 360 Lacing anatomically conforms to the foot for a tailored fit regardless of foot shape. Half length low profile syncro Stability Frame. NEW 1:1 Energy Foam cushions the forefoot upon impact and then returns energy back to the runner. SKYDEXR heel crash pad.