Pretty awesome reflective collars.
Available in 5 colours and against light they reflect a range of colours, even works against the sun.
Xsmall: collar length 1.7x 35cm (25-31cm)
Small: collar length 2.2x 45 (33-41cm)
Medium: collar length 2.7x 55 (39-49cm)
Large: collar length 3.2x 65(49-59cm)
 
It also has a metal plate so you can engrave your pets name or contact no. Great product for night walkers
Also available in the same style leash and harness set