Icelandair cabin bag recommendations

Hi all. I know icelandair can be super strict with their cabin bags (55x40x20). Does anyone have any suggestions for cabin bags they've used without issue (doesnt matter if it's a bit smaller than the guides)? I have an small it luggage that is technically withing dimension but I think the wheels may kick out beyond the 20cm allowance and really don't want to get stung with a check fee..