The hooks are strongly made of the toughest materials. Two spiral steel shafts, one inside the other, wound in opposite directions,make up the shaft. Corkscrew tip is tempered and threaded to the shaft which makes it replaceable. Available in 7 sizes and also as a set Osborne No. 1103F that comes with 1 each of sizes 1, 2 & 3. Don’t struggle with stubborn packing. Tips only are also sold separately.