Cellerman corkscrews This group of old corkscrews are known as cellerman corkscrews. Your fingers grasp the loop & then muscle power extracts the cork. A simple, slim shanked unmarked cellerman corkscrew, can be found quite easily for under a fiver. More interesting variants with fancy shanks, finger holes, buttons & bearing the makers stamps drive the price steeply upwards.
Roundlet corkscrews can be found in a variety of forms but typically they are of a cigar like shape & have a threaded capsule that opens to reveal the worm. Once opened the worm is pulled out, the capsule is then closed & acts as the handle. The majority of roundlet corkscrews were manufactured with a nickel finish but other materials were also used such as celluloid, wood, silver & even gold.