This is a thick stainless steel ruler. Material: SUS304 cold rolled material Size: 3mm x 30mm x 1m Hole: 8mm Weight: Approximately 680g The cold rolled material has a hairline finish with a dull luster, giving it a high-quality feel. Since it is SUS304, it will not rust even when wet. The corners are rounded because it is long and potentially dangerous. Due to its thickness, cutter blades are less likely to dig in or ride up. Please also use it for marking lines with a marking needle or marker. Thank you.