These electrodes are re-usable (hundreds of times). Connect the electrodes to a TP sensor and position them beneath the cap. Electrogel is applied to the electrode by the use of a syringe with a blunt needle. The alternative is just using Nuprep and Ten20.
NeXus Minicap EEG Electrodes TP are packed per set of 5 electrodes. Clean the electrodes with Ivory or lukewarm water.