What Cypher said
With the rough Bark wood items you also need to check for nails. Personally I find a lot of those barkwood items not well made and break but the shelf and steps are good, as are bendy bridges. This is the Ferplast Sin Guinea pig house. It comes flatpack and fits together like a jigsaw (so the roof lifts off - although the last one I had the roof was very stiff and needed sanding to make it fit).
https://www.amazon.co.uk/Ferplast-Gu...9999455&sr=8-1
This Trixie house has a lift off roof and it's very popular. Zooplus used to sell it but don't seem to at the moment. It's good for a dwarf hamster. For a Syrian you need to knock out the middle compartment to make the centre room bigger
https://www.amazon.co.uk/Trixie-6201...9999693&sr=8-1