A spectacle blind is a safety device used to isolate a section of line or piece of equipment when the line or equipment needs to be inspected or removed from service. It is different than a valve in that the blind is a permanent or long term isolation device.

Jointly they perform the same function as a Spectacle Blind as essentially a simplistic valve. The Spade or Spacer is fitted in the line between two flanges and is bolted in place. The Spacer is used when the line is required open and the PaddleBlind or Spade is installed when the line is required blocked or closed.