The Master Lock® S3923 blind flange lockout device is a physical, best practice solution for pipeline maintenance. The adjustable cup allows for a secure fit that conceals and locks out access to nuts holding a blind in place. Workers can perform maintenance with confidence that the blind they placed on a pipeline will not be removed until all workers have removed their padlocks. 4-locking holes allow for multiple workers to lockout device at one time. Master Lock® Blind Flange Lockout Device, Medium, Aluminum with Hardened Steel Slide Bar, Black/Red/Silver