DonFiber ST Type I High performance steel fibers with hooked ends for reinforcement of concrete and mortar (Formerly known as ST Fiber Type 1) You might also be interested in DonFiber ST300 High performance corrugated steel fibers for reinforcement of concrete and mortar DonFiber PP Ultra Ultra-fine, high performance monofilament polypropylene fibers DonFiber PP Macro E High-performance corrugated macro polypropylene fibres DonFiber PP-F High-performance fibrillated polypropylene fibers