Go to: TrainingSweeps.com for more information.

Hurdle Sweeps™ are a soft brush edge along the top of the hurdle which provide instant technique feedback. The athlete receives tactile and audible feedback - and a coach gets visual and audible information.
Interchangable brushes (sweeps) provide 5", 3" and/or 1" edges over the top of the actual hurdle board. The 3" sweep can be used as an actual height when the hurdle is set one notch down.
Intro set includes 3 attachment fixtures and three 3"sweeps. 
Sweep sections are replaceable.
Various drills listed on website - printable pdf.