The 78381 2-Port Cuvette Holder accept any 10 mm path length cuvettes. Light is coupled to and from the Cuvette Holders via fibers with 78382 Collimating Assemblies, which must be purchased separately. The collimators are necessary as the cuvette holders do not accept SMA terminated fibers, directly. The Collimators improve system efficiency; the first collimates the diverging output from the delivery fiber and the second focuses the collimated light into the collection fiber. It has a 1/4-20 tapped hole and 4 through holes.