What is the version of the following sentence with correct punctuation?

Castor type Swivel castor or a castor with doubleaction brake diameter 125 mm a 100 mm diameter castor will be available at the end of this year
Castor type: Swivel castor or a castor with double-action brake, diameter 125 mm (a 100 mm diameter castor will be available at the end of this year)