The best device hands down for passing knots in ropes easily and efficiently. Bead blasted and anodized for long wearing friction this lowering device offers tie-off capability. Special risers on the bottom keep it off the ground while in use. Works with virtually any size life safety rope. Not to be used for rappelling.  
Key features:
• Aluminum tubing and stainless steel
• Passes knots
• Runs multiple ropes
• Ties off any rescue load