The date code of the Supra Plus SL family of headsets will be located on the speaker, under the ear cushion. If a binaural model, the code will be on the microphone side. The first number represents the month (01=January, 02=February…). The two numbers following the dash represent the year (05=2005). Next is the model of the headset. An “HW251” represents the SupraPlus HW251 model and “HW261” represents the Supra Plus HW261 model. If an “N” is present, the headset is a noise-canceling model. If an “R” is present, the headset has been re-manufactured or replaced by Plantronics.
This also applies to the older H251, H251N, H261, H261N corded headsets.