Q: Do I need to add Anti Rotation Notches?

A: No, You do not need the anti rotation notches. A properly torqued GracePESDs will be sufficient to prevent the unit from rotating. The hole can be made with a standard 30.5mm punch. 

If you prefer to add anti rotation notches, Grace has partnered with Z-Tech Panel Punches to offer two punches with internal notches that match the below specifications.  There is a Single Notch Version (P/N uDL-1210-KEY157-GP) and a 4 Notch Version (P/N uDL-1210-KEY157-GP4) that can be used.  If this is a new panel that is being cut, use the diagram below with a laser cutter or water jet to cut out the notches.