Rectangular cells are used for most UV/VIS routine analysis. By far the most common type of cell, they have two windows clear and conform to international standard dimension. The 10mm pathlength size should fit most instruments that use rectangular cells. Available pathlengths are from 1mm to 100mm. Check with your instrument manual to see if you need an adaptor for longer pathlength cells.
Standard Rectangular cells are the most commonly cells used. The have two polished windows and a full interior width used in most instruments.