The Lovibond® 400640 Powder Cell Holding Fixture is designed to hold a cell for liquid or powder measurement. The fixture is designed specifically for an Optical Circular Sample Cell (400740). The cell is enclosed in a black chamber which prevents ambient light from affecting the measurement. The fixture attaches to Lovibond® Models RT300, 400 & 500 Spectrophotometer Series. The spectrophotometer must be mounted in the Lovibond® 400620 Benchtop Stand.