Forty mm UV quartz cell, part no. UVQC-40(1), Path length=40 mm; Exterior W, L and H=12.5, 42.5 and 45 mm; Interior W and L=10 and 40 mm. Each cell is packaged in an individual plastic case with a PTFE lid. UV quartz cells have a "U-shaped" bottom and the Fluorimeter quartz cells have a "square bottom".