Probes include temperature compensation and a screw-on cap. Probe maintenance kit 628-280-14 comes with one 50 ml bottle of electrode filling solution, 2 membrane caps and 1 piece of cathode cleaning paper. Probe maintenance kit 627-690-20 comes with one 50 ml bottle of electrolyte solution, one 30 ml bottle of cleaning solution, 3 membrane caps, and 1 piece of cathode cleaning paper.