Mighty Mouse Swim Ring...Local auction steal for $1

I purchased these two Mighty Mouse swim rings/inner tubes last night at an auction for $1.00. I have been looking all over the internet for any information with no luck. There is a date of 1956 on them and includes other characters : Gandy Goose, Little Roquefort, Dinky, and Pearl Pureheart.
Any info would be great on these! Thanks!!!