Very poor construction. It appears that the holes for the allen screws were not drilled deep enough--it is impossible to screw them in all the way. I kept trying to force them in. In the process, one of the small boards on the front of the seat came off--the seat is made of a composite material--doesn't hold the frame very securely. I ended up using a lot of glue and clamps. The seats are still wobbly but will hopefully hold together.