This Technical Specification provides guidelines for the parameters to be specified for concentrator photovoltaic cells (both multijunction and single junction) and provides recommendations and references for measurement techniques. No attempt is made to determine pass/fail criteria for cells. The purpose of this specification is to define the performance and physical characteristics of concentrator cells. This specification may also be used for describing cell assemblies and receivers, but is not written to specifically address cell packaging. It is not intended to standardize the properties of the concentrator cells, but to standardize how the properties are communicated.