Drive Devilbiss | Able Assist SlingDrive Devilbiss Sling Able Assist Adjustable Size Enhance Safety and Comfort with an Adjustable Transfer Sling For added safety and confidence, model PT004 can be paired with an adjustable transfer sling. This setup features keyhole locks that fit onto the sling location anchors on each side of the handlebar. With three keyhole locks, the sling can be adjusted to accommodate users of different sizes. Key Features Keyhole locks: Fit onto the sling