Dirt, paint and other debris getting in your fill nipple works its way
through your HPA tank, destroying seals and o rings in both your tank
and marker. Prevent lost playing time and costly repairs with these
Rubber Molded HPA Fill Nipple Caps. They fits snug to keep crud out of
your tank and feature a convenient leash so you don't lose it on the
field or the tank filler doesn't set it aside and forget!. Assorted
colors, color may vary