Charles Leonard Cup and Sponge Envelope and Finger Moistener, Clear/Red (87001) Go to amazon.com Related posts The 16 best finger moistener sponge FeatureGreat for home, mailrooms and schoolsLeak proofPlastic cupPolyurethane sponge DescriptionIdeal for affixing stamps, labels and sealing envelopes. Sponge cup featues 3" wide sponge and shatterproof clear plastic cup.