The entry level Chiorda model from the 1970s' boom used the Simplex Prestige derailleur system. The higher models tended to use various Campagnolo derailleurs. The Prestige's Delrin body made it light and inexpensive to produce. It also provided an excellent bearing surface and they shifted very smoothly, right out of the box. However, they also flexed a lot and they always felt like something was going to break on the shifts to larger cogs. They also tend to get brittle as they age. The telltale sign is usually brown or grey discoloration, starting as spots. Repeated treatments with Armor-All can rejuvenate the cosmetic appearance in many cases.