As seen above:
2 x edge roller 
2 x connectors
 
The Multi-Unit Edge Roller is a low profile edge protection device featuring an alloy aluminium frame and rollers. For protection of your ropes, the Rescuetech Multi-Unit Edge Roller may be used as a single unit or paired up with multiple units to provide large-area protection. Units link together with the included rapid links or may be tied using flat webbing to provide long range protection.