These glow sticks are 6" long, the original glo stick size. They might be cheap but they glow very brightly and last for at least 8 hours.
These glow sticks taper from 20mm wide (25/32") at the base to 15mm (19/32") at the hook end. The hook is used to attach the glow stick to yourself or to fix the supplied string to. If you're a glow stringer you'll probably be attaching your favourite brand of shoe lace before astounding your fellow ravers with your skills.
These glow sticks have been fully certified in the UK.