Pictured below are the three Convertible Connection Chain styles; Wheat, Oval and Double Link laid across my hand.
These next five images show (1) Oval Link Convertible Connection Chain 33" doubled back/fully extended, (2) Wheat Convertible Connection Chain 31" with the clasps close together draped over my hand, (3) Oval Link Convertible Connection Chain 33" with one side fully extended and the other doubled, (4) Double Link Convertible Connection Chain 33" with both clasps clasped on to the centerpiece, (5) Serling Connection Chain 16" clasped on to a Safest Place Charm.
The 31" Convertible Connection Chains are about 15-17" doubled and the 33" Convertible Connection Chains are about 6-18" doubled back. With both clasps clasped onto the centerpiece they are exactly 31" or 33".
The centerpieces add length to the necklace as a whole and the centerpiece in all but one of these photos is Petite Seed & Petal which is about 2".