The pegs are 7.5cm long and the grade 201 stainless steel wire that they are made of is 2mm in diameter. They don't break or fall apart, because the whole peg is made up out of just one single piece of wire.
If you live close to the ocean with the salty air and you want to leave the pegs out on the clothes line all the time, you should rather go for the grade 304 or 316 (marine grade) stainless steel wire pegs which are also available in my shop.
Be assured that these pegs will still be there when all the wooden and plastic ones are gone.