the 1552 is a folding prop in plastic/nylon - these soft props are highly desireable compared to the pimped carbon look props! Why you ask? It's a complicted aerodynamic reason, but trust us - you WANT a flexible prop for high speed flying/movie work - when speed runs are mixed with hovering Ops (Carbon Props only do well in hovering). With a new advanced airfoil design and stronger materials.
Excludes balancing - you need to pair these off - then balance them using a point balance beam technique - then store them together in their matched and balanced pairs - pro-tip from multiWiicopter.com