A few flaws - door not fit for purpose
I read a few reviews which mentioned the door not fitting and leaving a big gap, so I've taken I picture of the door fitted as intended (which leaves a massive gap for the smells to escape) and fitted backwards as someone else mentioned (much better this way but still has between 2-5mm gap around the door). Cat filter fits well and the tray is extremely roomy even for my bigger cat who weighs (5.5kg.....big boned, not fat!) :-)
For £15 it is good value even with the door issue.