Ergotron standing desks

The Z Mini is the small one: 31 inches wide, 15.8 deep, 12.5 inches of straight-up lift on a Z-shaped frame with a hand-brake lever. Because the lift is vertical rather than arcing forward, it does not sweep across your desk as it rises, which matters when the desk is small enough that something is always in the way. The limits are honest and severe. Twelve and a half inches of lift is not enough to reach a comfortable standing height for most people from a normal 29-inch desk — by the standing-elbow rule its 42.5-inch ceiling suits someone around 5 ft 8 in and nobody taller — and 25 lb covers a laptop or one 24-inch monitor. It is the right product for a laptop user in a small space who wants to stand for twenty minutes at a time, and the wrong one for a permanent workstation.

Best for: A laptop user in a small space who wants to stand occasionally rather than all day.

Ergotron's Constant Force mechanism is a coiled spring tuned to the weight on the surface, so the desk rises and falls with one hand at whatever speed you move it, with no motor, no controller and no power lead. Set it up anywhere — a warehouse, a classroom, a room with no free outlet — and it never needs a firmware update or a replacement control box. For the twenty inches between 30.6 and 50.6 that is a genuinely excellent mechanism. The problem is where those twenty inches sit. A 30.6-inch minimum is above the height of an ordinary fixed desk, so by the seated-elbow rule this desk does not lower far enough for anyone under about 6 ft 4 in to sit at comfortably. Treat it as a standing desk that can drop to perching height, not as a sit-stand desk, and it makes sense. Expect it to fail you if you bought it to fix a too-high desk.

Best for: A standing-first workstation, or anywhere mains power and control boxes are a nuisance.

The TX is the converter that solves the two problems most risers have. It rests only two inches above the desk when lowered, so it does not permanently raise your keyboard when you are sitting — most converters add three or four inches you can never get rid of. And its keyboard deck hangs below the work surface and tilts back, keeping the monitor-to-keyboard relationship correct as the whole thing rises, where a single-shelf riser puts your keyboard and screen at the same height and forces you to look down at both. The X-shaped lift is spring-assisted, so it moves with one hand and needs no power. What it cannot do is lower your sitting height, because it sits on the desk you already have. The 40 lb rating covers a single monitor up to 30 inches and a laptop, not a dual-arm setup.

Best for: A fixed or rented desk where the sitting position must stay untouched.