https://www.nextind.com/itemdetail/10900-659AZ
Starrett | 10900-659AZ | 3-1/2" x 3" x 3" Heavy-Duty Magnetic Base Indicator Holder Rigid Arm...
Shop Next Industries for Starrett, 10900-659AZ, Magnetic Bases, Rigid Arm, 3in. Base Height, 3-1/2in. Base Length, V-Bottom Style, 15in. Max Reach, 250 lbs....