The Deflector Generator is a block added by Engineer's Toolbox. The Deflector Generator will generate Deflector blocks above it. By default, it will generate 3; however, placing more Deflector Generators underneath will increase the number of Deflector blocks by 1 per added Generator until the maximum number of 7 Deflectors.
The Deflector block acts like a ghost block in that it can be entered. When an entity enters a Deflector block, it will make a loud clicking sound. Although the official Engineer's Toolbox Manual notes this will cause damage, it in fact does not, only damaging hostile mobs. Passive mobs and players take no damage and can easily pass through. Deflector blocks can attach to each other in a way similar to Iron Bars.
Giving a Redstone signal to any part of the Deflector Generator will disable it's functionality.