Basic Metal Silver Plated. The chain is 3mm diameter approx, The screw parts on the chain are 4mm diameter for stopper beads. The end of the chain where the beads thread on also is 4mm diameter. 18cm = 7.08" 19cm = 7.48" 20cm = 7.87" 21cm = 8.27" 52cm = 20.47"
