SeatPosts
A seatpost has a simple job, hold your saddle at exactly the angle you want despite pedalling and road bumps trying to dislodge it. To achieve this, a seatpost has to have 2 adjuster bolts mounted fore-aft. This allows the stresses to be shared but more importantly angle adjustment is almost infinite. Any single bolt post or 2 bolts side by side design is a waste of your money and potentially dangerous, avoid.