Abstract: An insulating device (10) for a bicycle water bottle (28) comprises a cylindrical sidewall (12) and a bottom (32). A slit runs down the sidewall (12) to allow the insulating device (10) to be fitted around a bottle (28) and cage (30). A strapping mechanism (20, 22, 24 and 26) is used to hold the slit closed and to attach the insulating device (10) adjacent the cage (30).