Back in the 1960s, my father's 1-23B had a glass tube (IIRC, 2-3 cm diameter--may have been a test tube with one end cut off) with rubber stoppers in each end, each of which had a metal/plastic tube inserted to connect up with the standard clear plastic instrument tubing.

Each spring he filled the glass tube with silica gel crystals (not sure if he baked the old crystals to drive out moisture and reused them or just used new). The objective was to prevent moisture from entering his Cosim pellet vario. Pellet varios were notoriously sensitive to moisture, which sometimes caused the lightweight red/green pellets to stick in their tubes.

Today's varios aren't nearly as sensitive to moisture, apparently. So for all the wailing about too much technology in soaring, we've made some progress.

Chip Bearden