.625 x .625 bars, the holes being 3/16 to fit my larger wires/rods, thumb screws go into the bars. The stuff was a pain to machine, a local airsmith used a cnc mini mill on this stuff and we tried cleaning the edges from where we kinda sloppily cut it and we threw the mill out of line, with alot of coolant and using smaller drillbits then stepping up the stuff drilled kinda easy
