Suitable for dreadlocks which are 8mm - 11mm in thickness. There a slight variations to the hole size as listed below.
Tribal Bead: 3cm high, 8mm hole
Barrel Bead: 2.4cm high, 8mm hole
Groove Bead: 1cm high, 8mm hole
Striped Bead: 1cm high, 6mm hole
Stainless steel is a durable material but over time may tarnish/rust particularly if exposed to salt water and chlorine.
I thought it was very cool to package these all together save a few bucks and they are solid metal, the designs on the product are accurate to their pictures.