This is the most likely technical meaning. In chemistry, a vapor tube (sometimes abbreviated in catalogs or shorthand as "vap tube") is a critical glass component in a rotary evaporator (like the Heidolph Hei-VAP). The "tranny" part might be a slang shorthand for the transmission or drive system that rotates this tube.
It could refer to a specific custom part for a vaporizer (vape). A "tube" often refers to the mod (the cylindrical body) or the glass tank section , though "tranny" is not a standard industry term here and might be a niche brand name or slang for a "transparent" or "translucent" component. vap tranny tube
In cellular biology, VAP (Vesicle-associated membrane protein-associated protein) is a protein that helps tether different parts of a cell together, often forming tubular structures between the endoplasmic reticulum and other organelles. This is the most likely technical meaning
For example, Heidolph Hei-Vap Rotary Evaporator Vapor Tubes 24/40 It could refer to a specific custom part