Hello Voyageur. that is the Brand and type of tubing used to build your bike (or the one you are looking at. and the type of dropouts. Tange ( you pronounce it with a long A, soft G and silent E) is the name of the tubing manufacture. "double-butted" means that the wall of the tubing is thinker within a few inches of the ends than it is in the middle. this allows them to make the tube and thus the frame both strong and light. 'Chrome Moly' is the materiel the tubing is made of. and alloy of Chromium steel, except for the cheapest older "HiTen or "carbon steel" bikes almost all steel bikes are made with a type of ChromeMoly materiel. the "forged droupouts" means the dropouts were made out of a solid peice of metal that was forged in some mannerbasically a huge press with two molds and they 'hammer' the raw metal stock into shape rather then being cut. " double eyelets" simply means there is two threaded anchor points on each dropout for attaching a rack and or fenders.

does this help?