UGEARS STEM Lab Model Kit - Creative 3D Wooden Puzzles for Adults, Teens and Children - DIY Mechanical Science Kit for Self Assembly - Educational and Engineering 3D Puzzles with App (Counter)

I think the age rating of 8+ is optimistic, I imagine a lot of 8 year olds would struggle to assemble this on their own. I helped assemble this with a 11 year old and we enjoyed it and the finished item was satisfying and worked correctly. But many of the parts are hard to assemble, and will require a lot of perseverance, and breaking one piece could be the end of it. So I would recommend it for 8+ where there is an adult to help when needed. But some adults might enjoy this as a gift also.

The kit consists of four wooden panels pre-cut by laser with press-out pieces. In addition there are rubber bands and wax to lubricate moving parts, and an easy to follow instruction book. The completed machine can count by operating a 'plunger' or by turning a wheel, and can be reset to zero (or to any number) by opening the front, which disengages the number wheels from their gears, enabling them to be turned independently. I don't know how long it will last, but it seems quite sturdy and even has rubber feet under it (made from a rubber band). Only negatives is some parts can be quite hard to press out (there is a tool provided), and it takes quite a bit of pressure to press some of the parts together. Also, eventually the rubber bands (that act like springs) will eventually decay and break, I expect. (It would probably be possible to repair it if this did happen). But worth 5 stars as an entertaining puzzle as well as educational.

All component parts are accurately laser cut and easy to push from the plywood sheets.Fitting the parts together feels smooth and positive and the assembly instructions are adequate. All in all an excellent way to fill a few hours.

Really enjoyed helping my nephew build this. Took a good few hours. He enjoyed it also and kept him of the computer for a day. Something different to do over lockdown.

The media could not be loaded.  Really enjoyed assembling this one, pieces were easy to pop out, and the instructions were very clear so easy to build. Was convinced it wouldn't work when completed, but i was wrong, really pleased with the result

Can be used in all types of measurements

Not yet assembled but looks good and promptly delivered.

My 7 year old grandson completed this, with a little help. Works well.