Liquid and abrasive gel solutions for preparing the skin before biopotential measurements are needed only with passive electrodes.  Active electrodes generally do not require skin impedance to be reduced for noise-free measurements.  These are not conductive electrolyte gels – they are intended to be used to abrade the skin and reduce skin contact impedance before affixing an electrode to the skin.  You may also need swabs or other implements to apply the prep solution.