The iRobot Roomba 980 comes with one spare side brush. I have to change to the spare side brush after one of the brush head of the original broke.
After changing to the spare side brush and scheduling it to clean just once, all the three brush heads broke. It is probably due to hardening of the rubber of the brush head that makes it so brittle.
John Ackerman, who is the official distributor of iRobot products in Singapore has a booth at IT Show 2017. At the booth, they only accept Cash or NETS payment only. I ended up getting my Braava Jet 240 from their website as the discounted price is applicable online as well. Delivery is fixed price at S$18, or you can pick it up from their office at, Blk 34 Upper Cross Street #04-138 Singapore 050034.